Answer:
the Architect should use {!$FieldType.lead.accessible} expression within the Visualforce page.
Explanation:
Visualforce is a framework that allows developers to build complex, user friendly interfaces that can be hosted primarily on the Lightning Platform
Controllers provide access to the data that should be displayed in a page, and can modify component behavior. a number of standard controllers are provided by The Lightning platform that contain functionality and logic that which are used for standard Salesforce pages
The Architect should Use the expression {!$FieldType.lead.accessible} within the Visualforce page.
To enforce Field-Level Security on a custom Visualforce page using the Standard Lead Controller, the Architect should define the page with the 'standardController' attribute set to 'Lead' and the 'extensions' attribute set to the appropriate Lead Controller extension. The 'with sharing' keyword should be used in the extension to enforce field-level security.
Explanation:To ensure Field-Level Security is enforced on a custom Visualforce page using the Standard Lead Controller, the Architect should define the Visualforce page with the 'standardController' attribute set to 'Lead' and the 'extensions' attribute set to the appropriate Lead Controller extension. Within the extension, the Architect can use the 'with sharing' keyword to enforce field-level security.
For example:
<apex:page standardController='Lead' extensions='LeadControllerExtension'>...</apex:page>public with sharing class LeadControllerExtension { ... }The 'with sharing' keyword ensures that the Visualforce page adheres to the Org-wide default settings and user's record-level access. This means that any field-level security restrictions defined for the Lead object will be enforced on the page.
The magnitude of vector A is 15.0 units and points in the direction 330° counterclockwise from the positive x-axis. Calculate the x- and y-components of this vector.
Answer:
[tex]V_{x}[/tex] = 12.99 , [tex]V_{y}[/tex] = -7.5
Explanation:
v=15units , θ=330°
the magnitude of the horizontal and vertical components are gotten by the formula below
[tex]V_{x}[/tex] = Vcosθ
[tex]V_{y}[/tex] = Vsinθ
[tex]V_{x}[/tex] = 15*cos330
[tex]V_{x}[/tex] = 12.99 (positive implies to the right)
[tex]V_{y}[/tex] =15*sin330
[tex]V_{y}[/tex] = -7.5 (negative implies downwards)
A roller coaster is climbing up the highest hill on its track. At which point will the front car of the coaster most likely have its greatest potential energy?
Answer:
top of the highest hill
Explanation:
The potential energy of an object is given by
[tex]U=mgh[/tex]
where,
m = Mass of the object
g = Acceleration due to gravity
h = Perpendicular distance from the ground.
It can be seen that the potential energy is proportional to height
[tex]U\propto h[/tex]
Here, the car will have maximum potential energy when it is at the maximum distance from the ground.
Hence, the car will be at the top of the highest hill
The front car of a roller coaster will have its greatest potential energy at the highest hill due to the stored gravitational potential energy that can be converted into kinetic energy as it descends.
Potential energy in a roller coaster system is greatest at the highest hill. At this point, the roller coaster's gravitational potential energy is at its maximum as it has the most stored energy that can be converted into kinetic energy as it descends. This transformation between potential and kinetic energy explains why the roller coaster's front car will most likely have its greatest potential energy at the top of the highest hill.
A clam dropped by a seagull takes 3.0 seconds to hit the ground. What is the seagull's approximate height above the ground at the time the clam was dropped?
The seagull dropped the clam from an approximate height of 44.1 meters above the ground. This was calculated using the physics formula for the height of a dropped object, considering the acceleration due to gravity.
Explanation:The subject of the question falls under Physics and it's related to the concept of gravitational acceleration. To calculate the height from which the seagull dropped the clam, we can use the physics formula for the height of a dropped object which is h = 0.5 * g * t^2.
Here, 'g' represents the acceleration due to gravity and has an approximate value of 9.8 m/s2, and 't' represents the time in seconds which is given as 3.0 seconds. So, inserting these values into the equation, we getThe seagull dropped the clam from an approximate height of 44.1 meters above the ground. This was calculated using the physics formula for the height of a dropped object, considering the acceleration due to gravity.
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When designing a user interface, the most important information should be placed in the ______ of the screen.
Answer:
upper-left corner
Explanation:
Most vital information are positioned in a place where users can view them clearly and without obstruction.
Q6) A speed skater moving to the left across frictionless ice at 8.0 m/s hits a 5.0-m-wide patch of rough ice. She slows steadily, then continues on at 6.0 m/s. What is the magnitude of her acceleration on the rough ice?
Final answer:
The magnitude of the acceleration of the speed skater on the rough ice is 2.8 m/s², calculated using the equation of motion.
Explanation:
To find the magnitude of the acceleration of the speed skater on the rough ice, we can use the equation of motion: v^2 = u^2 + 2as, where v is the final velocity, u is the initial velocity, a is the acceleration, and s is the displacement (width of rough ice).
Given that the skater's initial velocity (u) is 8.0 m/s, her final velocity (v) is 6.0 m/s, and the width of the rough ice (s) is 5.0 m.
Rearranging the equation for acceleration, we get a = (v^2 - u^2) / (2s). Substituting the given values, a = (6.0^2 - 8.0^2) / (2 * 5.0) = (-28) / 10 = -2.8 m/s2. The negative sign indicates deceleration, but since the question asks for the magnitude, the acceleration is 2.8 m/s2.
A particle of charge 3.53×10 −8 C experiences a force of magnitude 6.03×10 −6 N when it is placed in a particular point in an electric field. What is the magnitude of the electric field at that point?
Explanation:
Electric field is the ratio of force and charge.
Force, F = 6 x 10⁻⁶ N
Charge, q = 3.53 x 10⁻⁸ C
We have
[tex]E=\frac{F}{q}\\\\E=\frac{6\times 10^{-6}}{3.53\times 10^{-8}}\\\\E=169.97N/C[/tex]
Electric field at the location of the charge is 169.97 N/C
A ball is dropped off of a tall building and falls for 6 seconds before landing on the ground. Consider how far the ball falls in its first 3 seconds of free fall (from t = 0 s to t = 3 s) compared to how far it falls in its next 3 seconds (from t = 3 s to t = 6 s).
Answer:
In the last six seconds the ball will fall 3 times the distance it fell in the first 3 seconds
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration
g = Acceleration due to gravity = 9.81 m/s² = a
Total distance
[tex]s=ut+\dfrac{1}{2}at^2\\\Rightarrow s_1=0\times t+\dfrac{1}{2}\times 9.81\times 6^2\\\Rightarrow s=176.58\ m[/tex]
At t = 3 seconds
[tex]s=ut+\dfrac{1}{2}at^2\\\Rightarrow s_1=0\times t+\dfrac{1}{2}\times 9.81\times 3^2\\\Rightarrow s_2=44.145\ m[/tex]
In the next 3 seconds it will fall
[tex]s_2=176.58-44.145=132.435\ m[/tex]
Dividing the equations
[tex]\dfrac{s_2}{s_1}=\dfrac{132.435}{44.145}\\\Rightarrow s_2=3s_1[/tex]
In the last six seconds the ball will fall 3 times the distance it fell in the first 3 seconds
An out-of-control train is racing toward the Metropolis terminal train station - only Superman can help. The train has a mass of 75000 kg, and Superman has a mass of 115 kg. If the train has a velocity of 35 m/s, how fast does Superman have to fly in the opposite direction to stop it in a totally inelastic steel-Man-of-Steel collision?
Answer:
22826.09 m/s
Explanation:
From the law of conservation of momentum,
Sum of momentum before collision = sum of momentum after collision.
For an inelastic collision, the train and the superman have a common velocity
Note: For the superman to stop the train in an opposite direction, the common velocity after collision is zero, and such the total momentum after collision is zero
Therefore,
MU + mv = 0
MU = - mu............................................ Equation 1
Making u the subject of the equation
u = -MU/m......................................... Equation 2
Where M = mass of the train, U = initial velocity of the train, m = mass of the super man, u = initial velocity of the superman.
Given: M = 75000 kg, U = 35 m/s, m = 115 kg.
u = -(75000×35/115)
u = -22826.09 m/s
Note: The velocity is negative because the direction of the superman is opposite the direction of the train.
Hence the superman have to fly 22826.09 m/s in the opposite direction
Using the principle of conservation of momentum, Superman needs to fly approximately at a velocity of 22826 m/s in the opposite direction to stop the train.
Explanation:To stop the train, Superman needs to exert a force equal to the force being exerted by the train in the opposite direction. Using Newton's second law (F=ma), we can calculate the force needed to stop the train. The force needed can be found by multiplying the mass of the train by its acceleration, which is the change in velocity divided by the time taken to stop. In this case, the initial velocity of the train is given as 35 m/s and it needs to come to a stop, so the change in velocity is 35 m/s.
The question is asking how fast Superman must fly in the opposite direction to stop a moving train using the physics principle of conservation of momentum. In Physics, momentum is calculated using the equation momentum = mass * velocity. Since the train and Superman will collide and stop (an inelastic collision) total momentum before the collision should equal total momentum after the collision. Thus, the velocity of Superman equals (mass of train * velocity of train)/ mass of Superman, i.e., (75000 kg * 35 m/s) / 115 kg which is approximately 22826 m/s in the opposite direction.
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Solar energy breaks oxygen molecules apart in the stratosphere, releasing ____, which combine(s) with additional oxygen molecules to form ____.
Answer:
Oxygen atom
Ozone Molecule
Explanation:
The upper stratosphere and Mesosphere consist of the ozone layer. This layer helps in protecting us from the UV radiations of the Sun. This layer converts the UV radiation into heat energy.
The UV radiation breaks down the Oxygen molecules in oxygen atom which further combines with oxygen molecule to form Ozone. This Ozone molecule breaks to form Oxygen atom and Oxygen molecule. Oxygen atom further recombines with Oxygen molecule to make Ozone molecule. This is known as Ozone-Oxygen cycle. The excess energy is released as heat.
Everyday around 400 million metric tons of Ozone is produced through this cycle.
According to Prof. Bill Baker, the freedom of practicing professionals to make ethical decisions may not be worth much.unless they use a patterned approach
a. True.
b. False.
According to Prof. Bill Baker, the freedom of practicing professionals to make ethical decisions may not be worth unless they use a patterned approach for the sake of people and society and their welfare. This is true statement.
Answer: Option A
Explanation:
Ethical Decisions and their impact on society
When we talk about the professional fields; Engineers and Doctors comes first in our minds. The professional fields and persons make the roots of an ideal society for which they must take ethical decisions surely worth for the society.
The society has a right to expect ethical conduct from professionals. The conduct of taking ethical decisions must involve reasoning, planning and well execution. According to the Association for Practical and Professional Ethics, there are certain moral values that one must apply while practicing ethical decisions.
If Aristotle and Quintilian had a debate about rhetoric, which would likely argue that it is a means to communicate and persuade, and nothing more?
Answer:
Aristotle.
Explanation:
Aristotle is known as the father of rhetoric and it was actually his concept that the rhetoric is just the means of communications and persuade.
A water molecule can bond to up to _____ other water molecules by ____ bonds.
Answer:
A water molecule can bond to up to four other water molecules by hydrogen bonds.
Explanation:
A water molecule has angular structure about the oxygen atom which has 2 lone pair of electrons in a water molecule. Due to the repulsion of lone pairs we get the angle between the H---O bond as 109.47°.
Each of the hydrogen atom of water attracts one water molecule and the partial negative on the oxygen atom attracts two more water molecules form the electron deficit side to form a pentamer of tetrahedral structure placing itself at the center of the geometry and the bonded molecules at the vertices.
A hydrogen bond is an intermolecular bond. A water molecule bonds up to 4 water molecules by the hydrogen bond.
Hydrogen bond:It is an intermolecular bond that is formed between molecules that have a high difference in electronegativity. A water molecule has two hydrogens. These hydrogens, bond with the oxygen of another water molecule. The oxygen can bond the 2 hydrogens.Therefore, a water molecule bonds up to 4 water molecules by the hydrogen bond.
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The length of the assembly decreases by 0.006 in. when an axial a- force is applied by means of rigid end plates. Determine
(a) the magnitude of applied force,
(b) the corresponding stress in the steel core.
Final answer:
The stress in a steel rod due to an axial force is calculated based on the weight of the rod above the cross-section in question. Stress is calculated using σ = P / A, where P is the force and A is the cross-sectional area. The stress differs depending on the height from the lower end due to varying weights above the point.
Explanation:
The question is discussing a scenario in which a cylindrical steel rod undergoes axial deformation due to an applied force. This deformation could be either tension (elongation) or compression (shortening). The rod is experiencing stress and strain as a reaction to this force. To solve for the magnitude of the force and the stress in the steel core, we use principles from mechanical engineering, specifically statics and material science.
To find the normal stress in the steel rod at different heights when the rod is fastened vertically, we need to calculate the weight of the portion of the rod above the point in question. This is because the weight causes a compressive stress in the steel rod. The stress (σ) at a given point can be calculated using the formula σ = P / A, where P is the force (weight) acting on the cross-section and A is the area of the cross-section.
(a) For the cross-section 1.0 m from the lower end, only half of the rod's weight is above this point, and thus contributing to the stress.
(b) For the cross-section 1.5 m from the lower end, the portion of the rod above this point is 0.5 m, so only the weight of this segment contributes to the stress.
The innermost electron shell of an atom can hold up to _____ electrons. The innermost electron shell of an atom can hold up to _____ electrons. A.18 B. 1 C. 32 D.2 8
Answer:
D. 2
Explanation:
The innermost electron shell of an atom can hold up to 2 electrons.
All the elements in the periodic table have only two electrons in their inner most shell. The only exception is hydrogen because it has only one electron.
A -1.0@mC charge experiences a 10ni@N electric force in a certain electric field. What force would a proton experience in the same field?
Answer: A proton would experience the same magnitude of force.
Explanation: The equation relating Force F charge Q and Electric Field E, is given as
E = F/Q
The magnitude of the force felt would be the same since + and - charge as same magnitude from the question (-1C and +1C). But the direction of force of the proton which as a positive charge would be towards/same direction as the Electric Field.
You are hungry and decide to go to your favorite neighborhood fast-food restaurant. You leave your apartment and take the elevator 10 flights down (each flight is 3.0 m) and then go 15 m south to the apartment exit. You then proceed 0.2 km east, turn north, and go 0.1 km to the entrance of the restaurant.
Part A
Determine the displacement from your apartment to the restaurant. Use unit vector notation for your answer, being sure to make clear your choice of coordinates.
Take the beginning of the journey as the origin, with north being the y-direction, east the x-direction, and the z-axis vertical.
Part B
How far did you travel along the path you took from your apartment to the restaurant?
Part C
What is the magnitude of the displacement you calculated in part
Answer:
A) R = (200 i ^ + 100 j ^ + 30k ^) m , B) L = 223.61 m , C) R = 225.61 m
Explanation:
Part A
This is a vector summing exercise, let's take a Reference System where the z axis corresponds to the height (flights), the x axis is the East - West and the y axis corresponds to the North - South.
Let's write the displacements
Descending from the apartment
10 flights of 3 m each, the total descent is 30 m
Z = 30 k ^ m
Offset at street level
L1 = 0.2 i ^ km
L2 = 0.1 j ^ km
Let's reduce everything to the SI system
L1 = 0.2 * 1000 = 200 i ^ m
L2 = 100 j ^ m
The distance traveled is
R = (200 i ^ + 100 j ^ + 30k ^) m
Part B
The horizontal distance traveled can be found with the Pythagorean theorem for the coordinates in the plane
L² = x² + y²
L = √ (200² + 100²)
L = 223.61 m
Part C
The magnitude of travel, let's use the Pythagorean theorem for the sum
R² = x² + y² + z²
R = √ (30² + 200² + 100²)
R = 225.61 m
a typical flute is about 66 cm long . a piccolo is a very similar instrument ,through it is smaller, with a length of about 32 cm. how does the pitch of a piccolo compare to that of a flute?
Answer:
The Piccolo have higher frequency than Flute.
Explanation:
given,
length of the tube, L = 66 cm
length of the piccolo, L'= 32 cm
speed of sound = 343 m/s
A flute is open open tube with a fundamental frequency of ;
[tex]f = \dfrac{v}{2L}[/tex]
[tex]f = \dfrac{343}{2\times 0.66}[/tex]
f = 260 Hz
A piccolo is also an open open tube so, fundamental frequency is:
[tex]f = \dfrac{v}{2L}[/tex]
[tex]f = \dfrac{343}{2\times 0.32}[/tex]
f = 536 Hz
from the above calculation we can clearly see that the piccolo have much higher frequency than the flute.
now, The Piccolo have higher frequency than Flute.
Lance arrives at the airport (with flowers and balloons in hand) to welcome a friend. Her plane is delayed. While waiting, he notices that it takes 2 minutes 47 seconds to get down the hall on the moving sidewalk. while walking (not on the moving sidewalk) it took him 112 seconds. If he walks while on the sidewalk, how long (s) will it take him?
Answer:
t = 67.04 s
Explanation:
given,
time taken by Lace on the side walk = 2 min 47 s
= 167 s
time taken by the Lace while walking = 112 s.
now, time taken by the Lace when he is walking on the side walk = ?
Assume the distance be equal to 'd'
speed of Lace on side walk
we know, distance = speed x time
[tex]v_{sidewalk}=\dfrac{d}{167}[/tex]
speed of the lace while walking
[tex]v_{walking}=\dfrac{d}{112}[/tex]
time taken by Lace to cover the distance by walking on the side walk
[tex]t = \dfrac{distance}{v_{sidewalk}+v_{walking}}[/tex]
[tex]t = \dfrac{d}{\dfrac{d}{167}+\dfrac{d}{112}}[/tex]
[tex]t = \dfrac{167\times 112}{167+112}[/tex]
t = 67.04 s
time taken by the Lace walking on the side walk is equal to 67.04 s
Suzie Spacewalker hovers in space beside a rotating space station in outer space. Both she and the center of mass of the space station are at relative rest. If the space station is in Earth orbit, then Suzie____________
Answer:
is in the earths orbit
Explanation:
for Suzie to hover in space beside the rotating space station, she and the center of mass of the space station are at relative rest which happens when space station is in Earth orbit, hence she is in the earths orbit.
15. Explain how you can make a prediction for the atomic mass from only the atomic mass of each isotope and the ratios of isotopes that are present.
Answer:
The average atomic mass can be calculated from the exact atomic mass of each isotope by multiplying the mass each isotope by its relative abundance and then finding the sum of the result.
for example carbon has two major isotopes ;carbon 12 ,atomic mass with relative abundance of 98.9% and carbon 13 , atomic mass of with relative abundance 1.1%. The relative atomic mass is calculated below.
[tex]RAM = 12*\frac{98.9}{100}+13.003355 *\frac{1.1}{100}[/tex]
RAM=11.868 + 0.143036905
RAM=12.011036905amu
A chemist dissolves 377.mg of pure potassium hydroxide in enough water to make up 130.mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25°C.) Round your answer to 3 significant decimal places.
Answer:
The answer to your question is pH = 1.36
Explanation:
Data
Mass = 377 mg of KOH
Volume = 130 ml
pH = ?
pH = -log[H⁺¹]
Process
1.- Calculate the moles of KOH
molecular mass of KOH = 39 + 16 + 1 = 56 g
56 g of KOH --------------- 1 mol of KOH
0.377 g KOH ------------- x
x = (0.377 x 1) / 56
x = 0.0057 moles
2.- Calculate the concentration
Molarity = number of moles / volume
Molarity = 0.0057 / 0.13
Molarity = 0.044
3.- Calculate the pH of the solution
pH = - log [0.044]
pH = 1.36
Let's say you have two tuning forks which are supposed to produce the same frequency, 512 Hz. One is of good quality, but the other is cheaply made and vibrates at 510 Hz. If you bonk them both how many beats per second will you hear
Answer:
= 2 beats per seconds
Explanation:
From |f -f'| = modulus of the difference between the frequency given.f = 510Hz and f' = 512HzDifference between the frequency will give us the number of beat per seconds.i.e 2 beats per secondsThese also shows how to get the period of the tuning forks.
Two points (X and Y) in a fluid are at the same depth in a container. The pressure at X is greater than the pressure at Y. Which of the flowing must be true
Answer:
ρ_ x > ρ_ y
Explanation:
The pressure in a fluid depends on its depth with the equation
P = ρ g h
For two points at the same depth there may be several possibilities,
- the pressure is the same if the density of the fluid is equal in the two points
- The pressure is different if the fluid density is different at each point
In this case, as the point x has greater pressure than the point, the density of the fluid in Des is greater than the density of the fluid in Y
ρ_ x > ρ_ y
The names of the seven days of the week are derived from the names of the bodies of the solar system that are visible to the naked eye.
Answer:
Baja naja kanaka kanaka man's kana kana
Two blocks of masses M and 3M are placed on a horizontal, frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord holding them together is burned, after which the block of mass 3M moves to the right with a speed of 2.4 m/s. What is the speed of the block of mass M?
Answer:
The speed of the mass M is 7.2 meters per second
Explanation:
In this case because there aren't external forces on the system blocks-spring and the spring is light we should apply the conservation of linear momentum (P) that states:
[tex]\overrightarrow{p}_{f}+\overrightarrow{p}_{i}=0 [/tex] (1)
Momentum is mass (m) times velocity (v) ([tex] \overrightarrow{p}=m\overrightarrow{v}[/tex] (2)) and Initial momentum [tex] \overrightarrow{p}_{i} [/tex] is zero because the blocks are released form rest, so (1) is:
Using (2) on (1):
[tex]\overrightarrow{p}_{f}=M\overrightarrow{v_{M}}+3M\overrightarrow{v_{3M}}=0 [/tex] (3)
It's important to note that momentum and velocity are vector quantities so we should take care of directions, assuming right direction as positive, velocity of 3M mass is positive, and velocity of M mass is negative, (3) is:
[tex]M(-v_{M})+3M(v_{3M})=0 [/tex]
solving for [tex]v_{M}[/tex]
[tex] M(v_{M})=3M(v_{3M})[/tex]
[tex] v_{M}=\frac{3M(v_{3M})}{M}=\frac{3(2.4)}{1}[/tex]
[tex]v_{M}=7.2\frac{m}{s} [/tex]
An element forms an ionic compound with bromine having the formula XBr. If the mass number of the element X is 41 and the ion has 18 electrons, what is the element X and how many neutrons does it have?
Answer:
X is calcium and it has 21 neutrons
Explanation:
Calcium 41 is an isotope of calcium with mass number of 41 and atomic number of 20
Number of neutrons = mass number - number of electrons
The number of electrons is the same as the atomic number of the element (calcium)
Number of neutrons = 41 - 20 = 21
Analysis of an air sample reveals that it contains 3.5 x 10-6 g/L of carbon monoxide. Express the concentration of carbon monoxide in lb/ft3. (Use 1.00 lb = 454 g; 1 in = 2.54 cm)
To convert the concentration of carbon monoxide from g/L to lb/ft3, we need to perform two unit conversions: from grams to pounds and from liters to cubic feet. The concentration of carbon monoxide in lb/ft3 is approximately 2.7248 x 10-10 lb/ft3.
Explanation:To convert the concentration of carbon monoxide from g/L to lb/ft3, we can use unit conversion factors. First, we need to convert grams to pounds using the given conversion factor 1.00 lb = 454 g. Then, we can convert liters to cubic feet by using the conversion factor 1 L = 0.0353 ft3. Let's perform the calculations:
Therefore, the concentration of carbon monoxide in lb/ft3 is approximately 2.7248 x 10-10 lb/ft3.
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A 2.50-g bullet, traveling at a speed of 425 m/s, strikes the wooden block of a ballistic pendulum, such as that in the picture. The block has a mass of 215 g. (a) Find the speed of the bullet/block combination immediately after the collision. (b) How high does the combination rise above its initial position?
Answer:
4.88505 m/s
1.21629 m
Explanation:
[tex]m_1[/tex] = Mass of bullet = 2.5 g
[tex]m_2[/tex] = Mass of block = 215 g
[tex]v_1[/tex] = Velocity of bullet = 425 m/s
[tex]v_2[/tex] = Velocity of block
Here, the linear momentum is conserved
[tex]m_1v_1+m_2v_2=(m_1+m_2)v\\\Rightarrow v=\dfrac{m_1v_1+m_2v_2}{m_1+m_2}\\\Rightarrow v=\dfrac{2.5\times 10^{-3}\times 425+0.215\times 0}{2.5\times 10^{-3}+0.215}\\\Rightarrow v=4.88505\ m/s[/tex]
The speed of the combination of mass is 4.88505 m/s
The energy in the system is conserved
[tex]\dfrac{1}{2}(m_1+m_2)v^2=(m_1+m_2)gh\\\Rightarrow h=\dfrac{v^2}{2g}\\\Rightarrow h=\dfrac{4.88505^2}{2\times 9.81}\\\Rightarrow h=1.21629\ m[/tex]
The maximum height the combined mass will reach is 1.21629 m
Answer:
Explanation:
mass of bullet, m = 2.5 g
initial velocity of bullet, u = 425 m/s
mass of block, M = 215 g
(a) Let the speed of bullet block system is v
Use the conservation of momentum
m x u + M x 0 = (M + m) x v
2.5 x 425 = ( 215 + 2.5) x v
v = 4.89 m/s
(b) Let it rise upto height h
Use conservation of energy
Kinetic energy after collision = Potential energy
1/2 (M + m) v² = ( M+ m) x gx h
0.5 x 4.89 x 4.89 = 9.8 x h
h = 1.22 m
Polonium, the Period 6 member of Group 6A(16), is a rare radioactive metal that is the only element with a crystal structure based on the simple cubic unit cell. If its density is 9.232 g/cm3, calculate an approximate atomic radius for polonium―209.
Answer:
Approximate atomic radius for polonium-209 is 167.5 pm .
Explanation:
Number of atom in simple cubic unit cell = Z = 1
Density of platinum = [tex]9.232 g/cm^3[/tex]
Edge length of cubic unit cell= a = ?
Atomic mass of Po (M) = 209 g/mol
Formula used :
[tex]\rho=\frac{Z\times M}{N_{A}\times a^{3}}[/tex]
where,
ρ = density
Z = number of atom in unit cell
M = atomic mass
[tex](N_{A})[/tex] = Avogadro's number
a = edge length of unit cell
On substituting all the given values , we will get the value of 'a'.
[tex]9.232 g/cm3=\frac{1 \times 209 g/mol}{6.022\times 10^{23} mol^{-1}\times (a)^{3}}[/tex]
[tex]a = 3.35\times 10^{-8} cm[/tex]
Atomic radius of the polonium in unit cell = r
r = 0.5a
[tex]r=0.5\times 3.35\times 10^{-8} cm=1.675\times 10^{-8} cm[/tex]
[tex]1 cm = 10^{10} pm[/tex]
[tex]1.675\times 10^{-8} cm=1.675\times 10^{-8}\times 10^{10}=167.5 pm[/tex]
Approximate atomic radius for polonium-209 is 167.5 pm.
To find the approximate atomic radius of polonium-209, we can use its simple cubic crystal structure and the fact that its coordination number is six. By determining the mass contained within a unit cell and its volume, we can calculate the atomic radius.
Explanation:To approximate the atomic radius of polonium-209, we can use the fact that polonium crystallizes in a simple cubic structure. In this structure, each polonium atom contacts only its four nearest neighbors in its layer, one atom directly above it in the layer above, and one atom directly below it in the layer below. The coordination number for a polonium atom in a simple cubic array is six.
Since the coordination number is six, we can visualize a polonium atom at the center of a simple cubic unit cell, with one atom at each corner of the cube. The distance from the center of the unit cell to its vertices gives an approximation of the atomic radius of polonium-209.
Given that the density of polonium is 9.232 g/cm3, we can use the formula density = mass/volume to find the mass contained within the unit cell. With the knowledge that a unit cell contains one-eighth of a polonium atom at each of its eight corners, we can determine the volume of the unit cell. By dividing the mass contained within the unit cell by its volume, we can calculate the approximate atomic radius of polonium-209.
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What is the maximum number of lines per centimeter a diffraction grating can have and produce a complete first-order spectrum for visible light? (Assume that the range of visible wavelengths of light in air is 380 - 760 nm.)
Answer:
1315789.47368 lines/m
Explanation:
m = Order = 1
[tex]sin\theta[/tex] = 1 For maximum condition
[tex]\lambda[/tex] = Wavelength = 760 nm maximum
From Rayleigh criteria we have the expression for the gap
[tex]d=\dfrac{m\lambda}{sin\theta}\\\Rightarrow d=\dfrac{1\times 760}{1}\\\Rightarrow d=760\ nm[/tex]
The number of lines is the reciprocal of the slit distance
[tex]n=\dfrac{1}{d}\\\Rightarrow n=\dfrac{1}{760\times 10^{-9}}\\\Rightarrow n=1315789.47368\ /m[/tex]
The number of lines is 1315789.47368 per meter