Question 1

0 degrees Kelvin is
A)the temperature at which all random particle motion stops.
B)the temperature at which all particles move at the speed of light.
C)meaningless, a temperature outside the range defined for the Kelvin scale.
D)the temperature at which all particles transform into light.

Accepted Answer

0 degrees Kelvin, also known as absolute zero, is the temperature at which all random particle motion stops. It is the lowest possible temperature that can be achieved.

Question 2

Newton's second law states: sum of forces = mass × acceleration. If a known force was applied to an object with a known mass, how would you predict that object's acceleration?
A)acceleration = sum of forces / mass
B)acceleration = mass / sum of forces
C)acceleration = mass × sum of forces
D)Newton's second law is irrelevant for solving this problem.

Accepted Answer

According to Newton's second law, the acceleration is equal to the sum of forces divided by the mass. So, by rearranging the equation, we get the formula: acceleration = sum of forces / mass.

Question 3

Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun?
A)The mass of Earth is 6 × 1024 kg and Earth orbits the Sun in one year.
B)Earth is 150 million km from the Sun and orbits the Sun in one year.
C)Earth rotates in one day and orbits the Sun in one year.
D)Mercury is 0.387 AU from the Sun and Earth is 1 AU from the Sun.

Accepted Answer

Newton's version of Kepler's third law states that the square of the period of an orbit (in years) is proportional to the cube of the semi-major axis of the orbit (in astronomical units) and the mass of the central object (in solar masses). From the given facts in choice B, we know that Earth's period is one year and its semi-major axis is 1 AU (which is defined as the average distance from Earth to the Sun). Therefore, we can use Newton's version of Kepler's third law to solve for the mass of the Sun.

Question 4

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the mass of the second object were greater, what happens to the gravitational force between them?
A)The force increases.
B)The force decreases.
C)The force drops instantly to zero.
D)The gravitational force is not affected by the mass of the second object.

Accepted Answer

As the mass of the second object increases, the force of gravity between the two objects also increases, according to the equation Fg = G M1 M2 / d2. Therefore, the correct answer is A.

Question 5

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does M1 represent?
A)the distance, in meters, between the two objects
B)the diameter, in meters, of one of the objects
C)the mass of one of the objects

Accepted Answer

In the equation Fg = G M1 M2 / d2, M1 represents the mass of one of the objects.

Question 6

A rock held above the ground has potential energy. As the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?
A)The energy goes to producing sound and to heating the ground, rock, and surrounding air.
B)It is transformed back into gravitational potential energy.
C)The rock keeps the energy inside it in the form of mass- energy.
D)The energy goes into the ground, and as a result, the orbit of the Earth about the Sun is slightly changed.

Accepted Answer

When the rock hits the ground, the potential energy is converted into kinetic energy, which creates sound and heats up the ground, rock, and surrounding air. The energy is not transformed back into gravitational potential energy, as the rock is no longer held above the ground. The energy is also not kept inside the rock in the form of mass-energy, as the mass of the rock remains the same before and after the fall. The energy is not significant enough to change the orbit of the Earth about the Sun.

Question 7

Considering Einstein's famous equation, E = mc2, which of the following statements is true?
A)A small amount of mass can be turned into a large amount of energy.
B)You can make mass into energy if you can accelerate the mass to the speed of light.
C)One kilogram of mass represents 1 joule of energy.
D)Mass can be turned into energy, but energy cannot be turned back into mass.
E)It takes a large amount of mass to produce a small amount of energy.

Accepted Answer

This is the correct statement based on E=mc2. It means that a small amount of mass can be converted into a large amount of energy, and is the basis for nuclear energy and atomic bombs.

Question 8

When a spinning ice skater pulls in his arms, he spins faster because .
A)there exists an unbalanced reaction force
B)there is less friction with the ice
C)there is less friction with the air
D)his angular momentum must be conserved, so reducing his radius must increase his speed of rotation

Accepted Answer

According to the conservation of angular momentum, the product of rotational inertia and rotational velocity of a spinning object remains constant as long as no external torque is acting on it. When the ice skater pulls in his arms, he reduces his rotational inertia, meaning he must compensate by increasing his rotational velocity to maintain his angular momentum. This results in him spinning faster. Therefore, reducing the radius is the reason for the increased speed of rotation, as stated in choice D.

Question 9

As an interstellar cloud of hydrogen gas shrinks in size, its temperature increases
A)because gravitational potential energy is converted to thermal energy.
B)because thermal energy is converted to radiative energy.
C)because kinetic energy is converted to radiative energy.

Accepted Answer

As the interstellar cloud of hydrogen gas collapses under the force of gravity, its gravitational potential energy is converted into thermal energy, which increases its temperature. This process is known as gravitational heating.

Question 10

Consider the elliptical orbit of a comet around the Sun. Where in its orbit does it have the largest amount of total orbital energy?
A)when it is closest to the Sun
B)when it is farthest from the Sun
C)It always has the same total orbital energy.

Accepted Answer

The total orbital energy (the sum of kinetic and potential energy) of a comet in an elliptical orbit around the Sun remains constant throughout its orbit. This is a consequence of the conservation of energy in a closed system, where the Sun's gravitational field is the dominant force.

Question 11

If a gas cloud shrinks, its gravitational potential energy is converted into
A)chemical energy.
B)thermal energy and radiative energy.
C)kinetic energy and sound waves.
D)only radiative energy.

Accepted Answer

As a gas cloud shrinks, the particles within it collide more frequently and with greater force, causing an increase in temperature (thermal energy). This increase in temperature causes the gas cloud to emit radiation (radiative energy). Therefore, the gravitational potential energy is converted into both thermal and radiative energy.

Question 12

If I drop a golf ball and a bowling ball simultaneously from same height above the ground, what will happen? Neglect the effects of wind or air resistance.
A)The golf ball will hit the ground before the bowling ball.
B)The golf ball and the bowling ball will hit the ground at the same time.
C)The bowling ball will hit the ground before the golf ball.

Accepted Answer

According to Galileo's experiment, objects of different masses will fall with the same acceleration due to gravity in the absence of air resistance or any other external force. Therefore, the golf ball and the bowling ball will hit the ground at the same time.

Question 13

The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of
A)Newton's first law of motion.
B)Newton's second law of motion.
C)Newton's third law of motion.
D)the universal law of gravitation.
E)none of the above

Accepted Answer

Voyager 10's continued motion at a constant speed is explained by Newton's first law of motion, which states that an object in motion will remain in motion at a constant velocity unless acted upon by an external force. In this case, once Voyager 10 was propelled to its current velocity, there were no other external forces strong enough to slow it down or change its direction.

Question 14

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E = mc2?
A)A mass raised to a great height has a lot of gravitational potential energy.
B)An object accelerated to a great speed has a lot of kinetic energy.
C)A burning piece of wood produces light and heat, therefore giving off radiative and thermal energy.
D)A small amount of the hydrogen in a nuclear bomb becomes energy as fusion converts the hydrogen to helium.

Accepted Answer

Einstein's formula, E = mc2, deals with the conversion of mass to energy, which occurs during nuclear fusion reactions like those that fuel the sun and nuclear bombs. Therefore, the scenario involving the conversion of hydrogen to helium in a nuclear bomb is the one that would involve energy calculated with E = mc2.

Question 15

Newton's Second Law of Motion tells us that the net force applied to an object equals its _ .
A)mass times acceleration
B)mass times velocity
C)mass times energy
D)momentum times velocity

Accepted Answer

Newton's Second Law of Motion states that the net force applied to an object is directly proportional to its mass multiplied by its acceleration. Therefore, the correct answer is A, mass times acceleration. B, C, and D are incorrect since they do not match the equation of Newton's Second Law.

Question 16

Imagine a Star Wars type spaceship in orbit around a planet. Its engine suffers a severe malfunction, and explodes. What is the most physically realistic depiction of this event?
A)The spacecraft breaks apart, and the pieces continue to orbit the planet.
B)The spacecraft burns up in a giant fireball.
C)The spacecraft breaks in half and begins to sink down into the planet, like a sinking aircraft carrier.

Accepted Answer

In space, there is no atmosphere to cause a fireball upon explosion. Therefore, option B can be ruled out. Additionally, there is no force pulling the spaceship towards the planet that would cause it to sink down like an aircraft carrier. Therefore, option C can also be ruled out. The most physically realistic depiction would be for the spacecraft to break apart and for the pieces to continue to orbit the planet, following their respective trajectories.

Question 17

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?
A)It is less.
B)You are weightless.
C)It is the same.
D)It is greater.

Accepted Answer

When the elevator is traveling upward at a constant speed, the forces acting on you are balanced. This means that your weight on the elevator is the same as your weight on the ground. However, if the elevator were accelerating upward or downward, your weight would temporarily be greater or less than your normal weight, respectively.

Question 18

The astronauts feel weightless in the International Space Station, which orbits the Earth once every 90 minutes. Why?
A)because there is no gravity in space
B)because they and the space station are both falling around the Earth
C)because the gravity from the Moon cancels out the gravity from Earth
D)because they are moving so fast

Accepted Answer

The astronauts and the space station are both falling around the Earth, which creates the feeling of weightlessness. This is because they are in a constant state of freefall, where the Earth's gravity is continuously pulling them towards it, but their forward motion is constantly carrying them away.

Question 19

Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth?
A)Earth's orbit would be unaffected.
B)Earth's orbit would expand, and it would take more than one year to orbit the Sun.
C)Earth would change from a bound orbit to an unbound orbit and fly off into interstellar space.
D)The size of Earth's orbit would shrink, and it would take less than one year to orbit the Sun.

Accepted Answer

The gravitational force between two objects depends on their masses and the distance between their centers. If the Sun's mass remains the same and only its size changes, the gravitational force it exerts on Earth (and thus Earth's orbit) would remain unaffected.

Question 20

Newton's version of Kepler's third law states: In this equation, what do M1 and M2 represent?
A)the orbital period
B)the average distance between the two objects
C)the masses of the two objects
D)the universal gravitational constant

Accepted Answer

M1 and M2 represent the masses of the two objects in the equation.

Quiz 4: Making Sense of the Universe: Understanding Motion, Energy, and Gravity

0 degrees Kelvin is

Newton's second law states: sum of forces = mass × acceleration. If a known force was applied to an object with a known mass, how would you predict that object's acceleration?

Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun?

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the mass of the second object were greater, what happens to the gravitational force between them?

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does M1 represent?

A rock held above the ground has potential energy. As the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?

Considering Einstein's famous equation, E = mc2, which of the following statements is true?

When a spinning ice skater pulls in his arms, he spins faster because .

As an interstellar cloud of hydrogen gas shrinks in size, its temperature increases

Consider the elliptical orbit of a comet around the Sun. Where in its orbit does it have the largest amount of total orbital energy?

If a gas cloud shrinks, its gravitational potential energy is converted into

If I drop a golf ball and a bowling ball simultaneously from same height above the ground, what will happen? Neglect the effects of wind or air resistance.

The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E = mc2?

Newton's Second Law of Motion tells us that the net force applied to an object equals its _ .

Imagine a Star Wars type spaceship in orbit around a planet. Its engine suffers a severe malfunction, and explodes. What is the most physically realistic depiction of this event?

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?

The astronauts feel weightless in the International Space Station, which orbits the Earth once every 90 minutes. Why?

Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth?

Newton's version of Kepler's third law states: In this equation, what do M1 and M2 represent?