Answer: 784 J
Explanation:
Potential energy is expressed in:
PE= mgh
= 2 kg x 9.8 m/s² x 40 m
= 784 J
How fast is a ball going when it hits the ground after being dropped from a
height of 13 m? The acceleration of gravity is 9.8 m/s2
Answer:
16 m/s.
Explanation:
potential energy = kinetic energy.
mgh = ½mv².Cancelling m from both sides,
gh = ½ v².
9.8*13 = ½ v²
2(127.4) = v²
v² = 254.8
v = √254.8
v = 15.96 ~ 16m/s.
Answer:
v = 16.1 m/s
Explanation:
A car moves along a horizontal road with constant velocity v0 = v0xi until it encounters a smooth inclined hill, which it climbs with constant velocity v1 = v1xi + v1yj as indicated in the figure. The period of time during which the car changes its velocity is Δt.
Answer:
a ave = ( v1x - v0x ) i/Δt + v1y j/Δt
Explanation:
The acceleration of a body is the rate of change of the velocity of the body
The correct equation and value for the average acceleration vector and magnitude of the acceleration of the car are as follows;
Part (a) The average acceleration vector is [tex]\overset \rightarrow a_{av} =\dfrac{(v_{1x} - v_{0x})}{\Delta t} }\mathbf{i} + \dfrac{v_{iy} }{\Delta t} \mathbf{j}[/tex]
Part (b) The magnitude of the cars acceleration is [tex]\mathbf{ 2.\overline{518} }[/tex] m/s²
The reason the above values are correct is as follows:
Question: The parts of the question that appears to be missing are;
Part (a); The vector expression for the average acceleration in the time periods
Part(b); Find the magnitude of the cars acceleration
Variables:
v₀ₓ = 31 m/s
v₁ₓ = 31 m/s
[tex]v_{1y}[/tex] = 6.8 m/s
Δt = 2.7 s
Solution:
Part (a) The average acceleration vector, [tex]\mathbf{\overset \rightarrow a_{av}}[/tex], is given as follows;
[tex]Average \ acceleration \ vector, \overset \rightarrow a_{av} = \mathbf{\dfrac{\overset \rightarrow v_2 - \overset \rightarrow v_1}{t_2 - t_1}} =\dfrac{\Delta \overset \rightarrow v}{\Delta t}[/tex]
The given parameters in the question;
v₀ = v₀ₓ i
v₁ = v₁ₓ i + [tex]v_{1y}[/tex]j
∴ v₁ - v₀ = v₁ₓ i + [tex]v_{1y}[/tex]j - v₀ₓ i
The average acceleration vector becomes;
[tex]\overset \rightarrow a_{av} = \mathbf{\dfrac{\overset \rightarrow v_1 - \overset \rightarrow v_0}{\Delta t}} =\dfrac{(v_{1x} - v_{0x})\mathbf{i} + v_{iy} \mathbf{j}}{\Delta t}[/tex]
Therefore;
[tex]\mathbf{The \ average \ acceleration \ vector} \overset \rightarrow a_{av} =\dfrac{(v_{1x} - v_{0x})}{\Delta t} }\mathbf{i} + \dfrac{v_{iy} }{\Delta t} \mathbf{j}[/tex]
Part (b) The magnitude of the car's acceleration is given by plugging values of the variables v₀ₓ, v₁ₓ, [tex]\mathbf{v_{1y}}[/tex], and Δt in the above equation as follows;
[tex]\overset \rightarrow a_{av} =\dfrac{(31 \, m/s - 31 \, m/s)\mathbf{i} + 6.8 \, m/s \mathbf{j}}{2.7 \, s} = 2.\overline{518} \ m/s^2 \ \mathbf{j}[/tex]
The magnitude of the cars acceleration, a = [tex]\sqrt {(2.\overline{518} \ m/s)^2 } = \mathbf{ 2.\overline{518} \ m/s^2}[/tex]
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Explain why a law is accepted as fact, but a theory is not
In scientific discourse, a law is generally considered a descriptive generalization about how some aspect of the natural world behaves under stated circumstances. A theory, on the other hand, is a well-substantiated explanation of some aspect of the natural world that incorporates facts, laws, inferences, and tested hypotheses. The principal difference is that a law describes what happens and a theory explains why it happens.
Laws are accepted as fact because they are simple, true statements about how things occur in nature, usually summed up in a mathematical formula. They are typically based on empirical evidence from observations and experiments. For example, the Law of Gravity describes the attraction between two objects but doesn’t explain the mechanism. Theories, however, go through rigorous testing and are only sustained after consistent empirical support. They aim to provide the most reasonable explanation based on the evidence at hand. Consider the Theory of Evolution by Natural Selection - it explains the mechanisms behind the changes in species over time. Unlike a law, a theory can be adjusted or discarded if new evidence presents itself that doesn't align with the current theory. This flexibility is why theories, despite being well-supported, are not accepted as unchanging facts, but rather as the best explanations we have based on current knowledge.
The weather is warm and dry.
Which change would a cold front bring?
Answer:
rain or thunder
Explanation:
An example of a metalloid, elements with properties between metals and non-metals, is:
A. silicon
B. iron
C. oxygen
D. copper
Answer: A
Explanation: The answer is silicon
Answer: silicon
Explanation:
Calculate the force of gravity on a 5 kg mass at Earth's surface. The mass of the Earth is 6 x 1024 kg and its radius is
6.4 x 106 m. Do not use scientific notation. Round to a whole number (no decimal).
Force = 49 N
Explanation:
The gravitational force of attraction on the surface of earth F = G M m/R²
Here G = gravitational constant = 6.67 x 10⁻¹¹
M = mass of the earth and m = mass of the body on the surface of earth .
R = radius of earth
In this question
mass of earth = 6 x 10²⁴ kg and its radius = 6 x 10⁶ m
The values are substituted in the above equation
F = 6.67 x 10⁻¹¹ x 6 x 10²⁴ x 5 / ( 6 x 10⁶ )² = 49 N
The mass will be attracted by 49 N of force .
Naomi has increased the pressure on a solution of liquid and gas in a closed container. This will _______
amount of gas held in her solution
the
Increase
Explanation:
Naomi increasing the pressure on a solution of liquid and gas in a closed container will increase the amount of gas held in her solution.
Increase in pressure increases the solubility of gases in a solution.
Originally, the gases have their particles far apart from one another They move randomly all about without staying in the solution. Increasing their pressure brings the gases into more frequent collision with the solution. This will lead to an increase in amount of gas held in a solution.learn more:
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Increasing the pressure on a solution of liquid and gas in a closed container will increase the amount of gas held in the solution.
Explanation:Increasing the pressure on a solution of liquid and gas in a closed container will increase the amount of gas held in the solution. This is because an increase in pressure will result in more collisions between gas particles and the container walls, leading to a greater force being exerted on the walls. As a result, the pressure inside the container increases.
Estimate how much farther a person can jump on the Moon as compared to Earth if the take off
speed and angle are the same? The acceleration due to gravity on the moon is one-sixth what it
is on Earth.
Explanation:
Let us assume , an Object is thrown with initial Velocity u m/s and angle of θ above the horizontal level. The horizontal and vertical velocities are (x,y)
vₓ = v₀cos θ
[tex]v_{y}[/tex] = v₀ sinθ
now, the time when the object reaches the maximum height can be calculated from
[tex]v_{y}[/tex] = v₀ sinθ - at₀ = 0
t₀ = v₀ sinθ/a
thus, the total time in air is two times higher ; t = 2t₀ = 2 (v₀ sinθ) /a
the maximum distance can be calculated from this equation
X = vₓ t= v₀ cos θ x 2 (v₀ sinθ) /a
it implies x is inversely proportional to a.
we know the acceleration on the Moon is 1/6 th of Earth.the ratio between between maximal distance on the moon and on the earth is 6.
While in flight, a hot air balloon decreases its elevation by 83 meters and then increases its elevation by 83.7 meters,
Enter an inequality in the ber to compare the changes in elevation of the hot air balloon while in flight. this is math that i dont get pls help
Explanation:
Let the initial height of the balloon is L .
The lower level is L - 83 , because it goes 83 m downwards
The upper limit is L + 83.7 , because it goes up by 83.7 m
Thus the inequality becomes
L-83 ≤ L ≤ L + 83.7
what might be happening since 1880 for average global temperatures to increase
Answer:
The average global temperatures has increased since 1880 due to the emission of toxic gases in the atmosphere.
Explanation:
In average the global temperature of the earth has increased by 1 degree Celsius (2 degrees Fahrenheit). It includes the combined land and ocean's temperature.The main reason for this increase in global temperature is the emission of gases like carbon dioxide, CFC's and other greenhouse gases.Human activities, industrialization, modernization etc. are majorly responsible for this increment in temperature through the centuries.Roberta's next door neighbor has a theory that the best time to wash your car is late in the afternoon on Sunday. Is this a scientific theory? A. No, it is an opinion and is not testable. B. Yes, the car will stay clean for more of the week. C. Yes, the neighbor might be a scientist. D. No, it is better to wash cars on Saturday.
Answer: no, it is an opinion and is not testable (a)
Explanation:
i just got this question on Study Island
4. Elements that lie along the stair step line of the periodic table are
a. metals
c. liquids
b. metalloids
d. radioactive
The answer is B. metalloids
(boron, silicon, germanium, arsenic, antimony, tellurium, astatine, and polonium)
Final answer:
Elements along the stair step line of the periodic table are metalloids, with properties between those of metals and nonmetals. Metals are to the left and are conductive and malleable, while nonmetals are to the right and are typically poor conductors. Atomic radii decrease across a period and increase down a group. Option b
Explanation:
Elements that lie along the stair step line of the periodic table are known as metalloids. These elements exhibit properties that are intermediate between those of metals and nonmetals. Metals are typically found to the left of the metalloids, and they are generally malleable, shiny, and good conductors of heat and electricity.
On the other hand, nonmetals are located to the right of the metalloids and typically have opposite properties, such as being poor conductors of heat and electricity. The atomic radii of elements tend to decrease from left to right across a period because of the increasing positive charge in the nucleus, which pulls electrons closer. In contrast, atomic radii generally increase as you move down a group due to the addition of energy levels.
which is is not an effective way to gain fitness
A piece of cork has a volume of 10 cm cube. find the net force on the cork if it is completely submerged and then released.
(density of cork=200kg/m^3)
Answer:
Explanation:
The force required to submerge something underwater can be found from Archimedes principle:
FB=pwVg
Where FB is the buoyant force, pw is the density of water (1g/ml), V is volume of the water displaced, and g is gravity. The key here is V. The volume of water displaced by the cork is equal to the volume of cork. Therefore, the required force is
F=1 g/cm³ x 10 cm³ x 9.8 m/s²= 98 N
Which of the following is most closely related to the unit of time that humans call the month?
A.
the rotation of the Earth once on its axis
B.
the cycle of the Moon through all its phases
C.
the rotation of the Sun once on its axis
D.
the revolution of the Earth once around the Sun
Never mind found the answer
Answer:
the rotation of the earth once on its axis
By what mechanical adjustments can you speed up or slow down an old-fashioned grandfather
pendulum clock?
A)By changing the elongation angle of the pendulum
B) By giving the pendulum a slight nudge into or against its motion direction
C) By altering the length of the pendulum
D)
Either of the above works
E) None of the above works
C) By altering the length of the pendulum
Explanation:
The period of a simple pendulum is given by the equation
[tex]T=2\pi \sqrt{\frac{L}{g}}[/tex]
where
L is the length of the pendulum
g is the acceleration due to gravity
In this problem, we are asked which adjustmenet can be done to speed up or slow down the pendulum clock: that means, which adjustment can be done in order to change the period of the pendulum.
From the equation above, we notice that the period of a pendulum depends only on its length (and the acceleration of gravity). Therefore, its period can be changed only by changing the length of the pendulum. And so, the only correct answer is
C) By altering the length of the pendulum
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Baseball players wear batting gloves to increase
Answer:
They are worn because they help increase the quality of the grip on the bat.
Explanation:
the chances of cathcing the ball
Where is the input force
in the use of this simple
machine?
A. The feet planted in the snow
B.
The shovel lifted
C. The gravity pushing down on
the snow
D. The hands on the shovel
Answer:
the answer is B The shovel lifted
hope it helps!
The average speed of a train is 24.0km/hr. Suppose a train moving at this speed accelerates -0.20 m/s^2 until it reaches a speed of 8.0 km/hr. How long does it take the train to undergo this change in speed?
time = 2.2 sec
Explanation:
The initial speed of train = 24 km/hr = 24 x 1000/3600 = 20/3 m/sec
The final speed of train = 8 km/hr = 8 x 1000/3600 = 20/9 m/sec
The relation of motion
v = u + a x t
final velocity = initial velocity + acceleration x time
20/9 = 20/3 - 2 x t where t is time
Because the acceleration is negative
2 t = 20/3 - 20/9 = 40/9 or t = 20/9 sec = 2.2 sec
The time taken to decrease the speed from 24 km/hr to 8 km/hr is 2.2 sec approx
What do the lines making a circle around the low-pressure area indicate?
areas of equal altitude
areas of equal pressure
a stationary front
an occluded front
Answer:
Areas of equal pressure.
Explanation:
The line making a circle means equal pressure.
Final answer:
The lines around a low-pressure area on a weather map are isobars, indicating areas of equal pressure crucial for predicting weather conditions.
Explanation:
The lines making a circle around the low-pressure area indicate areas of equal pressure, also known as isobars. These isobars connect places with the same atmospheric pressure measurements, typically in millibars. On a weather map, isobars form almost circular shapes around low-pressure centers, like cyclones, and indicate areas where the pressure decreases towards the center.
Understanding these pressure patterns is essential for meteorologists to describe and predict weather, as they directly affect weather conditions. For instance, the approach of a low-pressure system often brings cloudiness, winds, and precipitation.
In which of the following conditions does
the car not accelerate?
A) A car moves at 80 km/h on a flat,
straight highway.
B) The car slows from 80 km/h to 35 km/h
C) The car turns a corner.
D) The car speeds up from 35 km/h to
80 km/h.
Answer:
The answer is A
Explanation:
If it goes 80km/h on a flat highway than it is not going any faster or slower.
When a car moves at 80 kilometers / hour on a flat, straight highway then the car would not accelerate, therefore the correct answer is option A.
What is acceleration?The rate of change of the velocity with respect to time is known as the acceleration of the object.
As per the second option when the car slows from 80 km/h to 35 km/h, then it would accelerate with negative acceleration.
When the car turns in the corner car would accelerate because there is a change in the velocity of the motion.
Similarly in the last option when a car speeds up from 35 km/h to
80 km/h, then it would generate acceleration because there is a change in the velocity with respect to the time.
The first option is the tye only case when the car would not accelerate because there is no change in the velocity of the car, thus the correct answer is option A.
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What does the standard deviation of a set of data tell you?
O
A. The number of experiments that were performed
O
B. How many data points there are in the set
O
C. The largest and smallest data values of the set
O
D. How much each data point differs, on average, from the mean
value of the set
SUBMIT
Answer:D
Explanation:
The standard deviation of a set of data tell you how much each data point differs, on average, from the mean value of the set. The correct option is D.
What is standard deviation?A standard deviation is a measure of how far apart the data is from the mean. A low standard deviation indicates that data is clustered around the mean, whereas a high standard deviation indicates that data is more spread out.
When data is distributed, standard deviation is important because it aids in understanding the measurements. The higher the standard deviation, the more evenly distributed the data is.
To summarize continuous data, the standard deviation is used in conjunction with the mean.
Furthermore, like the mean, the standard deviation is normally only appropriate when the continuous data is not significantly skewed or has outliers.
Thus, the correct option is D.
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A cylinder at left has balls stacked near its bottom with an arrow leading to a cylinder at right with balls evenly spaced throughout the cylinder. Which change of state is shown in the model? condensation evaporation sublimation deposition
Answer:
SublimationExplanation:
Your description corresponds to the picture attached.
In that model, the spheres represent atoms or molecules (is the same) of a substace. You can call them particles.
The particles tightly packed inside the cylinder of the left represent a substance in solid state whose particles are in a fix position and cannot move freely.
The particles randomly distributed throughout the cylinder on the right model a substance is gas state, where the particles occupy the whole space, moving freely.
Thus, the image depicts the change of a substance from solid state to gaseus phase. Such change is defined as sublimation.
Therefor, the answer is the third choice of your list: sublimation.
The change observed is the process of sublimation in the model. The correct answer is (c) sublimation.
In that model, the spheres represent atoms or molecules (the same) of a substance. You can call them particles.
The particles tightly packed inside the cylinder on the left represent a substance in a solid state whose particles are in a fixed position and cannot move freely.
The particles are randomly distributed throughout the cylinder on the right model a substance is a gas state, where the particles occupy the whole space, moving freely.
Thus, the image depicts the change of a substance from a solid state to the gaseous phase. Such change is defined as sublimation.
Therefore, the answer is the third choice of your list sublimation. The correct answer is (c).
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Which of the following is an example of a wheel and axle?
A. wheel barrow
B. automobile steering wheel
C. jar lid
D. pencil
Answer:
A. Wheel barrow
can't rlly explain-
The correct answer to the question is B. automobile steering wheel, as it represents a wheel and axle system where the steering wheel turns the axle (steering column), steering the vehicle.
A wheel and axle is a simple machine where a wheel is attached to a central rod known as an axle. The combination is designed to amplify force and can be found in many tools and machines. In the context of the provided options, B. automobile steering wheel is the correct answer, as it exemplifies a wheel and axle system. The steering wheel serves as the wheel that, when turned, rotates the axle (steering column) which ultimately steers the vehicle.
Other examples provided, such as a wheelbarrow, jar lid, and pencil, do not fit the definition of a wheel and axle as accurately. The wheelbarrow indeed has a wheel, but the axle's function and setup differ from the wheel and axle mechanism. The jar lid is more similar to a screw, and a pencil lacks the rotational mechanics involved in a wheel and axle system.
Which statement is the best interpretation of the ray diagram shown below?
A) A concave mirror forming a larger, virtual image
Explanation:
The figure is missing; see attachment.
There are two types of mirror:
Concave (converging) mirrors: a concave mirror is a mirror that reflects the light inwardConvex (diverging) mirrors: a convex mirror is a mirror that reflects the light outwardThe image formed by a mirror can also be of two types:
Real image: it is formed on the same side of the object, with respect to the mirrorVirtual image: it is formed on the opposite side of the object, with respect to the mirrorIn the figure of this problem (see attachment), we see that:
- The mirror reflects the light from the object inward --> so it is a concave mirror
- The image is formed on the other side of the mirror --> it is a virtual image
So the correct option is
A) A concave mirror forming a larger, virtual image
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Calculate the force of gravity between two planets with masses 5 x 1023 kg and 1 x 1022 kg when the distance
between them is 7 x 1016 m. Do not use scientific notation. Round to one decimal.
Answer:
68.1N
Explanation:
Check attachment
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Find the sum of the vectors:10km west.5 km south
Answer:
11.2km
Explanation:
Using Pythagoras theorem
R² = 10² + 5²
R² = 100 + 25
R² = 125
R = √125
R = 11.2km
The sum of the vectors 10 km west and 5 km south results in a resultant vector with a magnitude of 11.18 km and a direction of 26.57 degrees south of west, calculated using vector addition and trigonometric functions.
To find the sum of the vectors mentioned in the question, we need to apply the principles of vector addition. The first vector is given as 10 km west, which we can represent as (-10, 0) in Cartesian coordinates assuming the west is the negative x-direction. Similarly, the second vector is 5 km south, which we can represent as (0, -5) since south is the negative y-direction.
The sum of the vectors is found by adding their respective components. Hence, we add the x-components and the y-components separately:
x-component: -10 km (west) + 0 km (south's x-component) = -10 kmy-component: 0 km (west's y-component) + (-5) km (south) = -5 kmTherefore, the resultant vector from the sum of these two vectors is (-10 km, -5 km). To find the magnitude and direction of this resultant vector, we use the Pythagorean theorem and trigonometry. The magnitude (R) of the resultant vector is given by:
R = √((-10 km)² + (-5 km)²) = √(100 km² + 25 km²) = √(125 km²) = 11.18 km
The direction is found by calculating the angle to the negative x-axis (west) using the arctan function: θ = arctan(|y-component|/|x-component|) = arctan(5/10) = 26.57 degrees south of west.
The distance from the start point to the destination is 11.18 km, and the direction is 26.57 degrees south of west.
what would the velocity of a bullet that strikes a tin can 350 meters away in 0.25 seconds
Answer:
87.5 m/s
Explanation:
350m * 0.25s = 87.5 m/s
A real car moving at 10 km/h has more momentum than a toy car moving at the same speed because the real car ____.
A. generates less friction
B. has greater mass
C. has less mass
D. has greater forward motion
Answer:
The answer is B (has greater mass)
The real car has more momentum because it has greater mass.
Explanation:The correct answer is B. The real car has greater mass.
Momentum is defined as the product of an object's mass and its velocity. In this case, both the real car and the toy car are moving at the same speed of 10 km/h. However, since the real car has greater mass, it will have a greater momentum.
For example, let's say the real car has a mass of 1000 kg and the toy car has a mass of 100 kg. The momentum of the real car would be 1000 kg × (10 km/h) = 10,000 kg km/h, while the momentum of the toy car would be 100 kg × (10 km/h) = 1000 kg km/h. Therefore, the real car has more momentum than the toy car.
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100 ml of water is initially at 20°C. 30,000 J of heat is added to the water. What is temperature change for the water?
Answer:
Therefore the new temperature of the water is 91.67°C
Explanation:
Specific heat of water = 4.186 joule /gram °C
The equation to calculate change of temperature
Q=s×m×ΔT
Q = the amount of heat = 30,000 J
s= Specific heat of water = 4.186 joule /gram °C
m = mass of the water = volume ×density=(100×1)gram =100 gram
ΔT = the change of temperature = (T-20)
Therefore,
30000= 4.186×100×(T-20)
⇔(T-20)= 71.67
⇔T = 71.67+20
⇔T = 91.67
Therefore the new temperature of the water is 91.67°C