Explain what it means when we say a substance is magnetic.
Answer:
the substance that produces the magnetic field.
Explanation:
what is the hottest plant
PLEASE HELP!!!! Scientists launch a rocket, and they monitor its acceleration and the force exerted by its engines. As the rocket gets higher, the monitors show that the acceleration of the rocket is increasing but the force exerted stays the same. How do Newton’s laws explain why the scientists could expect this to happen?
The total force stays the same, but the action force is increasing as the reaction decreases.
The mass of the rocket decreases as fuel is burned, so the acceleration increases.
The inertia of the rocket increases, which reduces the force needed to change its speed.
The reaction force is increasing as fuel is burned, which causes a greater acceleration.
The force exerted is constant because the mass of the rocket decreases as fuel is burned, so the acceleration increases.
What is the relationship between force mass and acceleration?The relationship between force, mass, and acceleration is given by Newton's second law and stated mathematically as follows:
Force = mass × accelerationAs the rocket accelerates, fuel is burnt and the mass of the rocket reduces. Thus, the force exerted remains constant.
Therefore, the mass of the rocket decreases as fuel is burned, so the acceleration increases.
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Answer:
b
Explanation:
A car sits in an entrance ramp to a freeway, waiting for a break in the traffic. The driver sees a small gap between a van and an 18-wheel truck and accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, moves in a straight line, and has a speed of 25.0 m/s when it reaches the end of the ramp, which has length 129 m.
What is the acceleration of the car?
If an object has a mass of 38 kg, what is its approximate weight on earth?
does the term indivisible still describe the atom
All simple machines are variations of two basic machines.
True
False
...?
Simple machines are not variations of two basic machines; there are actually six types of simple machines: levers, pulleys, screws, inclined planes, wedges, and wheels and axles.
Explanation:False. Simple machines are not variations of two basic machines. In fact, there are six types of simple machines: levers, pulleys, screws, inclined planes, wedges, and wheels and axles.
A spaceship which is 50,000 kilometers from the center of Earth has a mass of 3,000 kilograms. What is the magnitude of the force of gravity acting on the spaceship? (The value of G is 6.673 × 10-11 newton meter2/kilogram2. The mass of Earth is 5.98 × 1024 kilograms.) 400 newtons 478 newtons 500 newtons 1595 newtons
Answer:
The correct option is [tex]478N[/tex]
Explanation:
Between two objects of a certain mass exists a force call the gravitational force. This force is the ''attraction'' force between the objects.
The equation to calculate this force is :
[tex]F_{G}=\frac{G.m_{1}.m_{2}}{d^{2}}[/tex] (I)
Where [tex]F_{G}[/tex] is the gravitational force.
Where G is the gravitational constant.
[tex]m_{1}[/tex] and [tex]m_{2}[/tex] are the masses of each object.
And [tex]d[/tex] is the distance between the objects (In fact is the distance between the mass centroid of each object).
In order to calculate the gravitational force, we need to replace the data in the equation.
The distance [tex]50000km[/tex] is equal to :
[tex]50,000km.(\frac{1000m}{1km})=50,000,000m[/tex]
Now, if we replace in the equation (I) all the data :
[tex]F_{G}=\frac{(6.673).(10)^{-11}\frac{Nm^{2}}{kg^{2}}.3000kg.(5.98).10^{24}kg}{(50,000,000m)^{2}}=478.854N[/tex]
[tex]F_{G}=478.854N[/tex] ≅ 478 N
We find that the magnitude of the force of gravity acting on the spaceship is 478 N.
A machine has a mechanical advantage of 4.5. What force is put out by the machine if the force applied to the machine is 800 N?
A-0.006 N
B-180 N
C-805 N
D-3600 N
The correct answer to the question is D).3600 N.
CALCULATION:
As per the question, the mechanical advantage of the machine MA = 4.5.
The force applied to the machine [tex]F_{i} =\ 800\ N[/tex].
We are asked to calculate the output force of the machine .
Let the output force is denoted as [tex]F_{o}[/tex].
The mechanical advantage of a machine is defined as the force amplification of a machine by using certain mechanical devices.
Mathematically it is defined as the ratio of output force to the applied or input force.
Hence, mechanical advantage MA = [tex]\frac{f_{o}} {f_{i}}[/tex]
Hence, the output force is calculated as -
[tex]f_{0}=\ MA\times f_{i}[/tex]
[tex]=\ 4.5\times 800 N[/tex]
[tex]=\ 3600\ N[/tex] [ANS]
Hence, the output force is 3600 N.
Answer:
The answer is d
Explanation:
Sound waves travel through air in a pattern of squeezing in and spreading out.
True
False
What is the efficiency of a device that gives you 10 units of useful energy for every 100 units you put in it?
A. 1
B. 0.5 What is the efficiency of a device that gives you 10 units of useful energy for every 100 units you put in it?
A. 1
B. 0.5
Answer: 0.1
Explanation:
i have this question and it’s the only answer not listed.
As objects grow farther apart, what happens to the force of gravity between them?
After one species disappears the other species in the ecosystem.....
The disappearance of one species in an ecosystem can lead to increased competition, growth of different species communities, or even the extinction of other related species. In extreme cases, it could result in the loss of the whole ecosystem.
Explanation:After one species disappears from an ecosystem, other species present in that ecosystem can be faced with a variety of scenarios. In some cases, a species that was competing with the now-extinct species for resources might thrive due to the lessened competition (scenario d and c). This could lead to a shift in the ecosystem's structure, particularly if the extinguished species was a dominant one.
Alternatively, another mature community with different species may quickly grow in place of the original community (scenario b). Therefore, in an ecosystem, the extinction of one species can lead to the emergence of new species or change the abundance of existing ones.
However, it's crucial to remember that ecosystems are a delicate balance of interactions between species, loss of a single species could lead to the extinction of related species as well (scenario on plant extinction). In extreme cases, the entire ecosystem could disappear (scenario of ecosystem diversity), which has significant environmental and economic impacts.
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If a plane can travel 450 miles per hour with the wind and 410 miles per hour against the wind, find the speed of the plane without a wind and speed of the wind?
Niagara Falls is a good example of
a.
kinetic energy being converted into potential energy.
b.
potential energy being converted into kinetic energy.
c.
energy being lost.
d.
energy being created.
the train accelerates from 30 km/h to 45 km/h in 15 secs. a. find its acceleration. b. distance it travels during this time ...?
Answer :
(a) The acceleration is, [tex]0.278m/s^2[/tex]
(b) Distance it travels during this time is, 156.225 m
Solution for part (a) :
Formula used :
[tex]a=\frac{v-u}{t}[/tex]
where,
a = acceleration
v = final velocity = [tex]45Km/hr=45\times \frac{5}{18}=12.5m/s[/tex]
u = initial velocity = [tex]30Km/hr=30\times \frac{5}{18}=8.33m/s[/tex]
t = time = 15 s
Now put all the given values in the above formula, we get
[tex]a=\frac{(12.5-8.33)m/s}{15s}=0.278m/s^2[/tex]
Therefore, the acceleration is, [tex]0.278m/s^2[/tex]
Solution for part (b) :
Formula used :
[tex]s=u\times t+\frac{1}{2}a\times t^2[/tex]
where,
s = distance traveled
Now put all the given values in this formula, we get
[tex]s=(8.33m/s)\times (15s)+\frac{1}{2}\times (0.278m/s^2)\times (15s)^2=156.225m[/tex]
Therefore, the distance it travels during this time is, 156.225 m
The acceleration of the train is 0.278 m/s² and the distance traveled by the train is 156.23 m.
The given parameters;
initial velocity of the train, u = 30 km/h = 8.33 m/sfinal velocity of the train, v = 45 km/h = 12.5 m/stime of motion, t = 15 sThe acceleration of the train is calculated by using the kinematic equation as follows;
[tex]a = \frac{\Delta v}{\Delta t}= \frac{12.5 - 8.33}{15} = 0.278 \ m/s^2[/tex]
The distance traveled by the train is calculated using the third kinematic equation as shown below;
v² = u² + 2as
[tex]s = \frac{v^2 - u^2}{2a} \\\\s = \frac{(12.5)^2 - (8.33)^2}{2(0.278)} \\\\s = 156.23 \ m[/tex]
Thus, the acceleration of the train is 0.278 m/s² and the distance traveled by the train is 156.23 m.
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A 1700kg rhino charges at a speed of 50.0km/h. What is the magnitude of the average force needed to bring the rhino to a stop in 0.50s?
An object is launched at 20 m/s from a height of 65 m. The equation for the height (h) in terms of time (t) is given by h(t) = -4.9t² + 20t + 65. What is the object's maximum height? the numeric answer only, rounded to the nearest meter.
Answer:
Maximum height will be 85 meter
Explanation:
given that height of an object is function of time and it is given as
[tex]h(t) = -4.9 t^2 + 20t + 65[/tex]
here we can write it as
[tex]h(t) - 65 = 20 t + \frac{1}{2}(-9.8) t^2[/tex]
now we can compare it with the kinematics equation
[tex]y(t) - y_o = v_i t + \frac{1}{2}at^2[/tex]
now if we compare the two equations then we will have
initial height of object = 65 m
initial velocity of projection = 20 m/s
acceleration = - 9.8 m/s/s
now for the maximum height at which its final speed will become zero is given as
[tex]v_f^2 - v_i^2 = 2a(h - h_o)[/tex]
[tex]0 - 20^2 = 2(-9.8)(h - 65)[/tex]
[tex]-400 = -19.6(h - 65)[/tex]
[tex]h = 85.4 m[/tex]
So maximum height in meter in nearest integer will be 85 m
Which statements describe characteristics of most metals? Check all that apply.
A They can be formed into wires.
B They are shiny.
C They are liquid at room temperature.
D They are good conductors.
can be easily shaped by hammering or pounding.
The answer is:
A. They can be formed into wires.
B.They are shiny.
D. They are good conductors
E.can be easily shaped by hammering or pounding.
The explanation:
Let's see the characteristics of the most metals:
1) the most metals can be hit by a hammer and form a thin sheets without breaking and this called malleability.
for example: Aluminium and copper
2) They can form into a very thin wires and this called ductility
for example: silvar , Aluminium and copper.
3) The metal can conduct the heat and the electricity very easy and quick, this mean that the meals are good conductor for the heat and electricity.
4)The metals like gold can be used at jewellery because it is very shiny.
5) and answer C is wrong because most metals are solid at room temperature.
Answer:
Option A, B, D and E are the characteristics of Metal
Explanation:
Some of the common characteristics of most of the metals are -
a) Most of the metal have lustrous surface which means they glitter in the presence of light for example - Iron, copper etc.
b) All metals are malleable which means they can be molded into different shape on beating for example copper can be converted into copper wire, jug, plates etc.
c) All metals are good carrier of charge and thus they are good conductors. These metals have valence shells electron which are free to move with a small force. Good metal conductors are copper , iron etc
d) Most of the metal are solid at room temperature.
A heavy crate rests on the bed of a flatbed truck. When the truck accelerates, the crate remains where it is on the truck, so it, too, accelerates. What force causes the crate to accelerate? ...?
Explanation:
A heavy crate rests on the bed of a flatbed truck. When the truck accelerates, the crate remains where it is on the truck, so it, too, accelerates. Due to the frictional force, the crate accelerates.
The force of friction is an opposing force. The force of friction depends on the coefficient of friction and the normal force acting on the object. The frictional force is of two types i.e sliding friction, static friction.
So, the frictional force causes the crate to accelerate.
Explain the steps of the life cycle of a star. Beginning with a nebula and ending with old age/death of a star, explain each step in a star’s life cycle
Final answer:
The life cycle of a star begins in a nebula and can end as a white dwarf, neutron star, or black hole, depending on its mass. The main sequence and red giant phases are critical stages in a star's evolution.
Explanation:
The life cycle of a star is a fascinating journey from birth to death, marked by transformations driven by nuclear processes and the gravitational pull. Understanding this cycle offers insights into the transient nature of celestial bodies and the forces shaping our universe.
Birth in a Nebula
Stars begin their lives in nebulae, massive clouds of gas and dust. Over millions of years, these clouds contract under gravity, heating up the core until nuclear fusion starts, marking the birth of a new star.
Main Sequence Stars
Once a star begins fusing hydrogen into helium in its core, it enters the main sequence phase, which can last billions of years, depending on its mass. Our Sun is currently halfway through this stage, expected to last a total of about 10 billion years.
Red Giant
As a star exhausts its hydrogen fuel, it expands into a red giant. For a Sun-like star, this phase will see it swell significantly, engulfing nearby planets.
Planetary Nebula and White Dwarf
Eventually, the outer layers of the red giant are ejected, leaving behind a planetary nebula. The core that remains cools and contracts into a white dwarf, marking the end of its life cycle. For stars like our Sun, this white dwarf will slowly fade over billions of years.
Massive Stars' Fate
Larger stars may undergo more dramatic endings, including supernova explosions, leaving behind neutron stars or black holes, depending on their mass.
what is the half life of a radioactive isotope that decreased to one-fourth its original amount in 100 year
Final answer:
The half-life of a radioactive isotope that decreases to one-fourth its original amount in 100 years is 50 years, as this duration represents two half-lives.
Explanation:
The half-life of a radioactive isotope is the time required for half the atoms of a radioactive sample to decay. If a radioactive isotope decreases to one-fourth of its original amount after 100 years, it means that two half-lives have passed (since one half-life leaves us with half the original amount, and another half-life would then leave us with one-fourth). Therefore, the half-life is 50 years. This exemplifies an exponential decay process, typical for radioactive substances.
1. In the circuit shown below, with each bulb holding a resistance of 100 ohms, how many amps of current are flowing? Express your number as a decimal. (See Figure)
2. Protons have positive charge, neutrons have negative charge, and electrons have no charge.
A. True
B. False
3. A complete electric circuit includes a voltage source, current, wires, and something to _________ the flow of current.
These are 3 questions and 3 answers.
Question 1.
Answer: I = 0.01 A
Explanation:
a) Data:
i) Type of circuit: series
ii) R₁ = 100 Ω
ii) R₂ = 100 Ω
iii) V = 2 V
iv) I = ?
b) Formulas
i) Equivalent resistance, R = R₁ + R₂
ii) Ohm's law, V = IR
c) Solution
i) R = 100Ω + 100Ω = 200Ω
ii) I = V / R = 2 V / 200Ω = 0.01 A
Question 2)
Answer: False.
Explanation:
The nuclear model of the atom states that the atom is neutral, and consists of a nucleus, which holds the protons and the neutrons, and the electrons which are around the nucleous (in regions called orbintals).
The electrons are negatively charged and the protons are positively charged.
The magnitudes of the charges of both electrons and protons are equal.
Therefore, for the atom be neutral, the neutrons cannot have charge.
Question 3.
Answer: oppose (or resist).
Explanation:
1) The most basic electrical circuit consists of a 1) potential difference (voltage) source, which gives the "impulse" to the charge to flow, 2) the wire, which is the medium through which the charge flows), and 3) a resistor.
The resistor is the element with "resistance" to the flow of charge, this is it resists or oppose the flow of charge.
Some components, like motors, filaments, buzzers, which content or are resistors per se, transform the current (flow of charge) in other useful forms of energy (motion, light, heat, sound).
The resistor meets Ohm's law which states R = V / I, at constant temperature.
What accounts for an increase in the temperature of a gas that is kept at constant volume ?
The correct answer to the question is : By increasing the pressure.
EXPLANATION:
Before answering this question, first we have to understand Gay lussac's law.
As per Gay lussac's law, the pressure of a gas increases or decreases by 1/273 th of its pressure at zero degree celsius; for every 1 degree celsius rise or fall of temperature at constant volume
In a simple way, the pressure is directly proportional to absolute temperature.
Mathematically P ∝ T. [ P = pressure and T = temperature]
Hence, increase in pressure at constant volume may increase its temperature.
The height of a helicopter above the ground is given by h = 2.80t3, where h is in meters and t is in seconds. At t = 1.55 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground? ...?
Answer:
The time is 4.692 sec.
Explanation:
Given that,
Height [tex]h = 2.80t^3[/tex]
Time t = 1.55 s
We know that,
The rate of change of height is the velocity.
So, the velocity is at t = 1.55 s
[tex]\dfrac{dh}{dt}= v = 3\times2.80\times(1.55)^2[/tex]
[tex]v=20.181\ m/s[/tex]
The velocity is upward with respect to the ground
We need to calculate the distance above the releasing point
Using equation of motion
[tex]v^2=u^2-2gs[/tex]
Put the value into the formula
[tex]s=\dfrac{v^2}{2g}[/tex]
[tex]s=\dfrac{20.181^2}{2\times9.8}[/tex]
[tex]s=20.77\ m[/tex]
The height of the helicopter releases a small mailbag
[tex]h=2.80\times(1.55)^3[/tex]
[tex]h = 10.43\ m[/tex]
We need to calculate the time
Using equation of motion
[tex]s=ut-\dfrac{1}{2}gt^2+h[/tex]
Put the value into the formula
[tex]0=20.77\times t-\dfrac{1}{2}\times9.8\times t^2+10.43[/tex]
[tex]t=-0.454,4.692[/tex]
On neglecting negative value of time
Hence, The time is 4.692 sec.
A 2.44 x 10^3 kg car requires 5.3 kJ of work to move from rest to some final speed. During this time, the car moves 27.4 m.
Neglecting friction, find
a) the final speed
b) the net horizontal force exerted on the car
Final answer:
The final speed of the car is 8.16 m/s and the net horizontal force exerted on the car is 2976.8 N.
Explanation:
To find the final speed of the car, we can use the work-energy principle. The work done on an object is equal to the change in its kinetic energy. Since the car starts from rest, its initial kinetic energy is zero, and the work done on the car is equal to its final kinetic energy.
Given that the car requires 5.3 kJ of work and has a mass of 2.44 x 10^3 kg, we can calculate the final kinetic energy using the equation:
Kinetic Energy = (1/2) * mass * velocity^2
By rearranging the equation, we can solve for the final velocity:
velocity = sqrt(2 * work / mass)
Substituting the values, we get:
velocity = sqrt(2 * 5300 / 2440) = 8.16 m/s
To find the net horizontal force exerted on the car, we can use Newton's second law, which states that force is equal to mass times acceleration. Since there is no vertical motion, the net force in the horizontal direction is equal to the mass times the acceleration.
Given that the mass of the car is 2.44 x 10^3 kg and the final velocity is 8.16 m/s, we can calculate the net horizontal force using the equation:
Force = mass * acceleration
Since the car starts from rest, the initial velocity is zero. Therefore, the acceleration is equal to the final velocity divided by the time taken to reach the final velocity. Given that the car moves 27.4 m, we can calculate the acceleration using the equation:
acceleration = velocity^2 / (2 * distance)
Substituting the values, we get:
acceleration = (8.16^2) / (2 * 27.4) = 1.22 m/s^2
Finally, we can calculate the net horizontal force:
Force = (2.44 x 10^3) * 1.22 = 2976.8 N
which nervous system consist of the brain and spine
A student squeezes several oranges to make a glass of orange juice. The juice contains pieces of orange pulp mixed with the juice. Explain why this drink can be considered a combination of a suspension and a solution.
Answer:
The juice contains sugars, plant pigments, and other chemicals dissolved in water. This is a solution. The pieces of orange pulp will rise to the top or settle to the bottom of the juice if it is allowed to sit. The pieces of pulp mixed with the juice form a suspension.
Explanation:
Final answer:
The orange juice can be considered a combination of a suspension and a solution because it contains both suspended particles of orange pulp and dissolved species, such as juice molecules and ions.
Explanation:
The orange juice can be considered a combination of a suspension and a solution because it contains both suspended particles of orange pulp and dissolved species, such as juice molecules and ions.
The orange pulp in the juice is an example of a suspension, which is a heterogeneous mixture composed of relatively large particles that are visible. The pulp particles are suspended in the juice and can settle out over time.
On the other hand, the juice itself is a solution, which is a homogeneous mixture where no settling occurs. The dissolved juice molecules and ions are evenly distributed in the liquid, giving it a transparent appearance.
Two masses, each weighing 1.0 × 103 kilograms and moving with the same speed of 12.5 meters/second, are approaching each other. They have a head-on collision and bounce off away from each other. Assuming this is a perfectly elastic collision, what will be the approximate kinetic energy of the system after the collision?
A. 1.6 × 105 joules
B. 2.5 × 105 joules
C. 1.2 × 103 joules
D. 2.5 × 103 joules ...?
Answer:
A. 1.6 × 105 joules
Final answer:
The total kinetic energy remains the same in a perfectly elastic collision. Since the two identical masses have identical speeds initially, their joined kinetic energies will be 1.6 × 10⁵ joules after the collision, same as before.
Explanation:
In a perfectly elastic collision, both momentum and kinetic energy are conserved. Since the two masses are identical and approach each other with the same speed, they will bounce back with the same speed after the collision, assuming no external forces act on the system. The kinetic energy of the system before the collision can be calculated using the formula KE = 0.5 × m × v² for each mass and then adding the two values together.
For each mass, KE = 0.5 × 1.0 × 10³ kg × (12.5 m/s)². Calculating this we get KE = 0.5 × 1.0 × 10³ × 156.25 = 78,125 Joules. Since there are two masses, the total kinetic energy would be 2 × 78,125 J = 156,250 Joules.
Immediately after collision, because it is perfectly elastic, the same amount of kinetic energy will be present. Therefore, the approximate kinetic energy of the system after the collision will be 1.6 × 10⁵ joules.
Ultraviolet light emits a total of 2.5 × 10^–17 J of light at a wavelength of 9.8 × 10^–7 m. How many photons does this correspond to?
Final answer:
To find the number of photons, we first calculate the energy of one photon using Planck's equation and then divide the total energy by this value. With the given wavelength, the energy per photon is 2.03 × 10⁻¹⁹ J, leading to approximately 1.23 × 10² photons for the total energy emitted.
Explanation:
To calculate the number of photons emitted at a given wavelength, we use the energy of a single photon and divide the total energy by this value. The energy (E) of a photon is related to its wavelength (λ) by the equation E = hc/λ, where h is Planck's constant (6.63 × 10⁻³⁴ J·s) and c is the speed of light (3.00 × 10⁸ m/s). Given a wavelength of 9.8 × 10⁻⁷ m, the energy per photon can be calculated. Then, the total number of photons is total energy / energy per photon.
First, we find the energy of one photon:
Energy per photon (E) = (6.63 × 10⁻³⁴ J·s) × (3.00 × 10⁸ m/s) / (9.8 × 10⁻⁷ m)E = 2.03 × 10⁻¹⁹ J per photonNext, we use the total energy to find the number of photons:
Number of photons = Total energy / Energy per photonNumber of photons = (2.5 × 10⁻¹⁷ J) / (2.03 × 10⁻¹⁹ J)Number of photons ≈ 1.23 × 10² photonsFinal answer:
To find the number of photons that correspond to 2.5 × 10⁻¹⁷ J of ultraviolet light at a wavelength of 9.8 × 10⁻· m, first calculate the energy per photon using Planck's formula, then divide the total energy by this value, resulting in approximately 1.23 × 10² photons.
Explanation:
To calculate the number of photons corresponding to 2.5 × 10⁻¹⁷ J of ultraviolet light at a wavelength of 9.8 × 10⁻· m, we must first determine the energy per photon using the formula E = hc/λ, where E is the photon energy, h is Planck's constant (6.626 × 10⁻4 J·s), c is the speed of light in a vacuum (3 × 10⁸ m/s), and λ is the wavelength of the light.
First, we calculate the energy per photon:
E = (6.626 × 10⁻4 J·s)(3 × 10⁸ m/s) / (9.8 × 10⁻· m) ≈ 2.026 × 10⁻ J per photon.
Now, we find the number of photons by dividing the total energy by the energy per photon:
Number of photons = Total energy / Energy per photon = (2.5 × 10⁻ J) / (2.026 × 10⁻ J/photon) ≈ 1.23 × 10² photons.