Question 1

Which statement must be true in order for a rocket to travel from Earth to another planet?
A)It must be launched from space, rather than from the ground.
B)It must have very large engines.
C)It must attain escape velocity from Earth.
D)It must carry a lot of extra fuel.

Accepted Answer

In order for a rocket to travel from Earth to another planet, it must achieve escape velocity from Earth. This is the minimum speed needed to break free from Earth's gravitational pull and travel through space. Launching from space, having large engines, or carrying extra fuel might be helpful in achieving escape velocity or reaching the other planet, but they are not necessary conditions for a successful journey.

Question 2

What is the acceleration of gravity at the surface of Earth?
A)9)8 km/s2 downward
B)9)8 km/s downward
C)9)8 m2/s downward
D)9)8 m/s2 downward
E)9)8 m/s downward

Accepted Answer

The correct unit for acceleration due to gravity is meters per second squared (m/s^2). Therefore, the only option that has this unit is D) 9.8 m/s^2 downward.

Question 3

Suppose you heat an oven to 400°F and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?
A)The water can transfer heat to your arm more quickly than the air.
B)The molecules in the water are moving faster than the molecules in the oven.
C)The oven has a higher temperature than the water.
D)The water has a higher temperature than the oven.

Accepted Answer

Water is a better conductor of heat than air. Therefore, the water can transfer heat more quickly to your arm than the air in the oven.

Question 4

The ultimate source of energy that powers the Sun is
A)chemical potential energy of hydrogen burning into helium.
B)thermal energy of the hydrogen atoms in the Sun.
C)mass energy of hydrogen fusing into helium.
D)kinetic energy of the orbital motion of the Sun.
E)gravitational potential energy of the contraction of the gas cloud that formed the Sun.

Accepted Answer

The ultimate source of energy that powers the Sun is the mass-energy of hydrogen fusing into helium through nuclear fusion in the core. This releases an enormous amount of energy in the form of light and heat.

Question 5

Momentum is defined as .
A)force times velocity
B)mass times speed
C)mass times acceleration
D)mass times velocity

Accepted Answer

Momentum is defined as the product of an object's mass and velocity. Therefore, the correct choice is D, mass times velocity.

Question 6

Newton's version of Kepler's third law states According to this, what observational information does one need in order to calculate the combined mass of a planet and its moon?
A)the orbital period and the density of the two objects
B)the radius of the two planets in meters and the average distance between them
C)the average distance between the two objects and the orbital period
D)It is impossible to determine the mass of any astronomical object.

Accepted Answer

According to Newton's version of Kepler's third law, the combined mass of a planet and its moon can be determined with the knowledge of the average distance between the two objects and their orbital period. Density and radius are not necessary for this calculation. Therefore, option C is the correct choice. Option A may be helpful in calculating individual masses, but not the combined mass. Option B is irrelevant and option D is incorrect.

Question 7

Approximately where is it currently high tide on Earth?
A)wherever it is currently noon
B)only on the portion of the Earth facing directly toward the Moon
C)on the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon
D)anywhere that ocean water laps upon the shore

Accepted Answer

High tide occurs on the portion of Earth facing directly toward the Moon (due to the gravitational pull of the Moon on the water) as well as on the portion facing directly away from the Moon (due to the centrifugal force generated by the Earth-Moon rotation system). This creates two bulges in the ocean, causing high tide on these portions of the Earth. The high tides move around the Earth as it rotates, so it is not limited to a particular time (like noon). However, not all areas experiencing high tide will necessarily have waves lapping on the shore.

Question 8

Newton's second law states: sum of forces = mass × acceleration. According to this, what property can you determine if you observe the acceleration of an object with a known mass?
A)the sum total of all forces acting on the object
B)the current velocity of the object.
C)the value of a single force acting on the object
D)the current location of the object

Accepted Answer

Newton's second law, F = ma, allows you to calculate the sum of all forces acting on an object if you know its mass and acceleration.

Question 9

The difference between speed and velocity is that _ _.
A)velocity is calculated using a physics equation
B)velocity also includes a direction
C)velocity is the same as acceleration but speed is different
D)they are expressed in different units

Accepted Answer

Speed is a scalar quantity which only tells us how fast an object is moving, while velocity is a vector quantity which not only tells us how fast an object is moving but also in what direction it is moving.

Question 10

According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them .
A)increases by a factor of 3
B)decreases by a factor of 9
C)increases by a factor of 9
D)decreases by a factor of 3

Accepted Answer

The universal law of gravitation states that the gravitational force between two objects is inversely proportional to the square of the distance between their centers. Therefore, if you triple the distance, the gravitational force decreases by a factor of $3^2 = 9$.

Question 11

The gravitational force that the Earth exerts on the Moon is equal and opposite to that which the Moon exerts on the Earth. Therefore, according to Newton's second law of motion,
A)the Moon and the Earth both have equal accelerations, because the forces are equal.
B)the Earth has a larger acceleration than the Moon, because it has a larger mass.
C)the Moon has a larger acceleration than the Earth, because it has a smaller mass.

Accepted Answer

Newton's second law states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass. Since the gravitational force between the Earth and the Moon is the same for both, but the Moon has a smaller mass, it experiences a larger acceleration.

Question 12

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 distance between two objects increases, 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 distance.

Accepted Answer

According to the equation Fg = G M1 M2 / d2, the gravitational force between two objects decreases as the distance between them increases. This is because the force of gravity is inversely proportional to the square of the distance between the two objects. Therefore, as the distance between them increases, the force of gravity decreases.

Question 13

Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit (well above Jupiter's atmosphere and far from all of Jupiter's moons.)Which of the following statements would be true?
A)Jupiter's gravity would capture the asteroid, making it a new moon of Jupiter.
B)Jupiter's gravity would suck in the asteroid, causing it to crash into Jupiter.
C)The asteroid's orbit around Jupiter would not change, and it would go out on the same unbound orbit that it came in on.
D)There is no way to predict what would happen.

Accepted Answer

The asteroid, being on an unbound orbit, means it has enough velocity to escape Jupiter's gravitational pull after passing by. Thus, it would continue on its original trajectory, unaffected in the long term by Jupiter's gravity.

Question 14

The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that .
A)the planets are always accelerating
B)the planets have angular momentum
C)the planets will eventually fall into the Sun
D)a force is acting on the planets

Accepted Answer

Newton's second law of motion states that an object will only accelerate if a force acts upon it. Therefore, since the planets are not traveling in a straight line, they must be experiencing a force. This force is in fact the force of gravity, which is pulling the planets towards the Sun and causing their orbits. The correct answer is D, "a force is acting on the planets".

Question 15

In which of the following cases would you feel weightless?
A)while falling from a roof
B)while accelerating downward in an elevator
C)while walking on the Moon
D)while parachuting from an airplane

Accepted Answer

The answer of In which of the following cases would...

Question 16

Why is Newton's version of Kepler's third law so useful to astronomers?
A)It tells us that more- distant planets orbit the Sun more slowly.
B)It allows us to calculate distances to distant objects.
C)It explains why objects spin faster when they shrink in size.
D)It can be used to determine the masses of many distant objects.

Accepted Answer

Newton's version of Kepler's third law allows us to determine the masses of many distant objects based on their orbital periods and distances. This is particularly useful for studying stars, planets, and other celestial objects that cannot be directly measured.

Question 17

What do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite)?
A)Orbital energy is the sum of the object's kinetic energy and its gravitational potential energy as it moves through its orbit.
B)Orbital energy is the object's kinetic energy as it moves through its orbit.
C)Orbital energy is the amount of energy required for the object to leave orbit and escape into space.
D)Orbital energy is a measure of the object's speed as it moves through its orbit.

Accepted Answer

Orbital energy is the sum of the object's kinetic energy and its gravitational potential energy as it moves through its orbit. Kinetic energy is the energy an object possesses due to its motion, while gravitational potential energy is the energy an object possesses due to its position in a gravitational field. As an orbiting object moves through its orbit, it experiences changes in both its kinetic and potential energy, which combine to give the object its total orbital energy.

Question 18

Why are astronauts weightless in the Space Station?
A)because the Space Station is constantly in free- fall around the Earth
B)because the Space Station is moving at constant velocity
C)because the Space Station is traveling so fast
D)because there is no gravity in space

Accepted Answer

Astronauts are weightless in the Space Station because the Station is in a constant state of free-fall around the Earth. This creates a sensation of weightlessness, despite gravity still existing in and around the Station.

Question 19

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does d represent?
A)the density of the smaller object
B)the universal gravitational constant
C)the distance between the two objects

Accepted Answer

In the equation Fg = G M1 M2 / d2, d represents the distance between the two objects. This distance is squared in the denominator, indicating that the force of gravity decreases with distance. The density of the smaller object and the universal gravitational constant (G) are not represented by the variable d in this equation.

Question 20

Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?
A)The ball's gravitational potential energy is greatest at the instant the ball leaves your foot.
B)The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point.
C)The ball's gravitational potential energy is greatest at the instant it returns to hit the ground.
D)The ball's gravitational potential energy is always the same.

Accepted Answer

The gravitational potential energy of an object is directly proportional to its height above the ground. At the instant when the ball is at its highest point, it is 10 meters above the ground and therefore has the greatest gravitational potential energy. At the moment the ball leaves the foot, its potential energy is zero, and at the instant it returns to hit the ground, its potential energy is again zero. Therefore, B is the correct choice.

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

Which statement must be true in order for a rocket to travel from Earth to another planet?

What is the acceleration of gravity at the surface of Earth?

Suppose you heat an oven to 400°F and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?

The ultimate source of energy that powers the Sun is

Momentum is defined as .

Newton's version of Kepler's third law states According to this, what observational information does one need in order to calculate the combined mass of a planet and its moon?

Approximately where is it currently high tide on Earth?

Newton's second law states: sum of forces = mass × acceleration. According to this, what property can you determine if you observe the acceleration of an object with a known mass?

The difference between speed and velocity is that _ _.

According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them .

The gravitational force that the Earth exerts on the Moon is equal and opposite to that which the Moon exerts on the Earth. Therefore, according to Newton's second law of motion,

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 distance between two objects increases, what happens to the gravitational force between them?

Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit (well above Jupiter's atmosphere and far from all of Jupiter's moons.) Which of the following statements would be true?

The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that .

In which of the following cases would you feel weightless?

Why is Newton's version of Kepler's third law so useful to astronomers?

What do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite) ?

Why are astronauts weightless in the Space Station?

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

Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?