Question 1

A hypothetical planet has a mass of one-half that of the earth and a radius of twice that of the earth.What is the acceleration due to gravity on the planet in terms of g,the acceleration due to gravity at the surface of the earth?

Accepted Answer

A) g 
B) g/2 
C) g/4 
D) g/8 
E) g/16

Question 2

A spaceship with a mass of 2.8 × 106 kg is traveling toward two spherical asteroids,each with a mass of 5.0 × 1016 kg,that are 40 km apart center-to-center.Its path is perpendicular to the line joining the asteroids and is aimed at the midpoint of that line.What is the net gravitational force exerted by the asteroids on the spaceship when the spaceship is 30 km away from that midpoint? (G = 6.67 × 10-11 N ∙ m2/kg2)

Accepted Answer

A) 12,000 N 
B) 8,000 N 
C) 16,000 N 
D) 6,200 N 
E) 18,000 N

Question 3

An astronaut drops a marble on the surface of the airless Planet Z-49 and observes that it takes 1.02 s for the marble to fall 2.00 m starting from rest.She also knows that the radius of Z-49 is 3.39 × 106 m.From this information,what will she determine for the mass of Z-49? (G = 6.67 × 10-11 N ∙ m2/kg2)

Accepted Answer

A) 3.30 ×  kg. 
B) 6.62 ×  kg. 
C) 4.62 ×  kg. 
D) 8.09 ×  kg. 
E) 9.95 ×  kg.

Question 4

An astronaut goes out for a "space-walk" at a distance above the earth equal to the radius of the earth.What is her acceleration due to gravity at that point?

Accepted Answer

A) zero 
B) g 
C) g/2 
D) g/4 
E) g/

Question 5

At a distance of 14,000 km from the center of Planet Z-99,the acceleration due to gravity is 32 m/s2.What is the acceleration due to gravity at a point 28,000 km from the center of this planet?

Accepted Answer

A) 8.0 m/s2 
B) 16 m/s2 
C) 128 m/s2 
D) 4.0 m/s2 
E) 2.0 m/s2

Question 6

At their closest approach,Venus and Earth are 4.20 × 1010 m apart.The mass of Venus is 4.87 × 1024 kg,the mass of Earth is 5.97 × 1024 kg,and G = 6.67 × 10-11 N ∙ m2/kg2.What is the magnitude of the gravitational force exerted by Venus on Earth at that point?

Accepted Answer

A) 1.10 × 1018 N 
B) 4.62 × 1028 N 
C) 5.43 × 1026 N 
D) 6.30 × 1020 N 
E) 1.72 × 1019 N

Question 7

Planet A has twice the mass of Planet B.From this information,what can we conclude about the acceleration due to gravity at the surface of Planet A compared to that at the surface of Planet B?

Accepted Answer

A) The acceleration due to gravity on Planet A must be twice as great as the acceleration due to gravity on Planet B. 
B) The acceleration due to gravity on Planet A must be four times as great as the acceleration due to gravity on Planet B. 
C) The acceleration due to gravity on Planet A is the same as the acceleration due to gravity on Planet B. 
D) The acceleration due to gravity on Planet A is greater than the acceleration due to gravity on Planet B,but we cannot say how much greater. 
E) We cannot conclude anything about the acceleration due to gravity on Planet A without knowing the radii of the two planets.

Question 8

As a 70-kg person stands at the seashore gazing at the tides (which are caused by the Moon),how large is the gravitational force on that person due to the Moon? The mass of the Moon is 7.35 × 1022 kg,the distance to the Moon is 3.82 × 108 m,and G = 6.67 × 10-11 N ∙ m2/kg2.

Accepted Answer

A) 0.24 N 
B) 0.024 N 
C) 0.0024 N 
D) 0.00024 N

Question 9

By how many newtons does the weight of a 100-kg person decrease when he goes from sea level to mountain top at an altitude of 5000 m? The mean radius of the earth is 6.38 × 106 m.

Accepted Answer

A) 0.60 N 
B) 1.5 N 
C) 2.6 N 
D) 3.6 N 
E) 9.8 N

Question 10

The captain of a spaceship orbiting planet X discovers that to remain in orbit at 
From the planet's center,she needs to maintain a speed of 
What is the mass of planet X? (G = 6.67 × 10-11 N ∙ m2/kg2)

Accepted Answer

A) 2.8 × 1019 kg 
B) 4.2 × 1017 kg 
C) 2.8 × 1016 kg 
D) 4.2 × 1014 kg

Question 11

When a spacecraft is launched from the earth toward the sun,at what distance from the earth will the gravitational forces due to the sun and the earth cancel? Earth's mass is 5.97 × 1024 kg,the sun's mass is 1.99 × 1030 kg,and the Earth-sun distance is 1.5 × 1011 m.

Accepted Answer

A) 1.3 × 108 m 
B) 2.6 × 108 m 
C) 1.3 × 1010 m 
D) 2.6 × 1010 m

Question 12

What is the gravitational force acting on a 59-kg person due to another 59-kg person standing 2.0 m away? We can model each person as a small sphere.(G = 6.67 × 10-11 N ∙ m2/kg2)

Accepted Answer

A) 5.8 × 10-8 N 
B) 8.5 × 103 N 
C) 1.2 × 10-7 N 
D) 9.8 × 10-10 N 
E) 2.0 × 10-9 N

Question 13

Suppose our sun had 4 times its present mass but the earth orbited it at the same distance as it presently does.What would be the length of the year on the earth under those conditions?

Accepted Answer

A) 1/4 as long as the present year 
B) 1/2 as long as the present year 
C) the same as the present year 
D) twice as long as the present year 
E) four times as long as the present year

Question 14

What is the distance from the center of the Moon to the point between Earth and the Moon where the gravitational pulls of Earth and Moon are equal? The mass of Earth is 5.97 × 1024 kg,the mass of the Moon is 7.35 × 1022 kg,the center-to-center distance between Earth and the Moon is 3.84 × 108 m,and G = 6.67 × 10-11 N ∙ m2/kg2.

Accepted Answer

A) 3.45 × 108 m 
B) 3.84 × 107 m 
C) 4.69 × 106 m 
D) 3.83 × 106 m 
E) 4.69 × 107 m

Question 15

Mithra is an unknown planet that has two moons,A and B,in circular orbits around it.The table summarizes the hypothetical data about these moons.What is the mass of Mithra? (G = 6.67 × 10-11 N ∙ m2/kg2)

Accepted Answer

A) 1 × 1022 kg 
B) 3 × 1022 kg 
C) 1 × 1023 kg 
D) 3 × 1023 kg 
E) 1 × 1024 kg

Question 16

Planet Z-34 has a mass equal to one-third that of Earth and a radius equal to one-third that of Earth.With g representing,as usual,the acceleration due to gravity at the surface of Earth,the acceleration due to gravity at the surface of Z-34 is

Accepted Answer

A) g/3. 
B) 3g. 
C) 6g. 
D) g/9. 
E) 9g.

Question 17

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars.If gm is the acceleration due to gravity at the surface of Mars,what is the acceleration due to gravity at the location of the satellite?

Accepted Answer

A) gm/9 
B) 0 
C) gm 
D) gm/3 
E) gm/16

Question 18

The reason an astronaut in an earth satellite feels weightless is that

Accepted Answer

A) the astronaut is beyond the range of the earth's gravity. 
B) the astronaut is falling. 
C) the astronaut is at a point in space where the effects of the moon's gravity and the earth's gravity cancel. 
D) this is a psychological effect associated with rapid motion. 
E) the astronaut's acceleration is zero.

Question 19

Satellite A has twice the mass of satellite B,and moves at the same orbital distance from Earth as satellite B.Compare the speeds of the two satellites.

Accepted Answer

A) The speed of B is twice the speed of A. 
B) The speed of B is one-half the speed of A. 
C) The speed of B is one-fourth the speed of A. 
D) The speed of B is equal to the speed of A. 
E) The speed of B is four times the speed of A.

Question 20

If Earth had twice its present mass but it orbited at the same distance from the sun as it does now,its orbital period would be

Accepted Answer

A) 4 years. 
B) 3 years. 
C) 2 years. 
D) 1 year. 
E) 6 months.

Exam 12: Gravity

A hypothetical planet has a mass of one-half that of the earth and a radius of twice that of the earth.What is the acceleration due to gravity on the planet in terms of g,the acceleration due to gravity at the surface of the earth?

An astronaut goes out for a "space-walk" at a distance above the earth equal to the radius of the earth.What is her acceleration due to gravity at that point?

At a distance of 14,000 km from the center of Planet Z-99,the acceleration due to gravity is 32 m/s².What is the acceleration due to gravity at a point 28,000 km from the center of this planet?

At their closest approach,Venus and Earth are 4.20 × 10¹⁰ m apart.The mass of Venus is 4.87 × 10²⁴ kg,the mass of Earth is 5.97 × 10²⁴ kg,and G = 6.67 × 10^-11 N ∙ m²/kg².What is the magnitude of the gravitational force exerted by Venus on Earth at that point?

Planet A has twice the mass of Planet B.From this information,what can we conclude about the acceleration due to gravity at the surface of Planet A compared to that at the surface of Planet B?

As a 70-kg person stands at the seashore gazing at the tides (which are caused by the Moon) ,how large is the gravitational force on that person due to the Moon? The mass of the Moon is 7.35 × 10²² kg,the distance to the Moon is 3.82 × 10⁸ m,and G = 6.67 × 10^-11 N ∙ m²/kg².

By how many newtons does the weight of a 100-kg person decrease when he goes from sea level to mountain top at an altitude of 5000 m? The mean radius of the earth is 6.38 × 10⁶ m.

The captain of a spaceship orbiting planet X discovers that to remain in orbit at From the planet's center,she needs to maintain a speed of What is the mass of planet X? (G = 6.67 × 10^-11 N ∙ m²/kg²)

When a spacecraft is launched from the earth toward the sun,at what distance from the earth will the gravitational forces due to the sun and the earth cancel? Earth's mass is 5.97 × 10²⁴ kg,the sun's mass is 1.99 × 10³⁰ kg,and the Earth-sun distance is 1.5 × 10¹¹ m.

What is the gravitational force acting on a 59-kg person due to another 59-kg person standing 2.0 m away? We can model each person as a small sphere.(G = 6.67 × 10^-11 N ∙ m²/kg²)

Suppose our sun had 4 times its present mass but the earth orbited it at the same distance as it presently does.What would be the length of the year on the earth under those conditions?

Mithra is an unknown planet that has two moons,A and B,in circular orbits around it.The table summarizes the hypothetical data about these moons.What is the mass of Mithra? (G = 6.67 × 10^-11 N ∙ m²/kg²)

Planet Z-34 has a mass equal to one-third that of Earth and a radius equal to one-third that of Earth.With g representing,as usual,the acceleration due to gravity at the surface of Earth,the acceleration due to gravity at the surface of Z-34 is

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars.If g_m is the acceleration due to gravity at the surface of Mars,what is the acceleration due to gravity at the location of the satellite?

The reason an astronaut in an earth satellite feels weightless is that

Satellite A has twice the mass of satellite B,and moves at the same orbital distance from Earth as satellite B.Compare the speeds of the two satellites.

If Earth had twice its present mass but it orbited at the same distance from the sun as it does now,its orbital period would be

Exam 12: Gravity

A hypothetical planet has a mass of one-half that of the earth and a radius of twice that of the earth.What is the acceleration due to gravity on the planet in terms of g,the acceleration due to gravity at the surface of the earth?

An astronaut goes out for a "space-walk" at a distance above the earth equal to the radius of the earth.What is her acceleration due to gravity at that point?

At a distance of 14,000 km from the center of Planet Z-99,the acceleration due to gravity is 32 m/s2.What is the acceleration due to gravity at a point 28,000 km from the center of this planet?

At their closest approach,Venus and Earth are 4.20 × 1010 m apart.The mass of Venus is 4.87 × 1024 kg,the mass of Earth is 5.97 × 1024 kg,and G = 6.67 × 10-11 N ∙ m2/kg2.What is the magnitude of the gravitational force exerted by Venus on Earth at that point?

Planet A has twice the mass of Planet B.From this information,what can we conclude about the acceleration due to gravity at the surface of Planet A compared to that at the surface of Planet B?

As a 70-kg person stands at the seashore gazing at the tides (which are caused by the Moon) ,how large is the gravitational force on that person due to the Moon? The mass of the Moon is 7.35 × 1022 kg,the distance to the Moon is 3.82 × 108 m,and G = 6.67 × 10-11 N ∙ m2/kg2.

By how many newtons does the weight of a 100-kg person decrease when he goes from sea level to mountain top at an altitude of 5000 m? The mean radius of the earth is 6.38 × 106 m.

The captain of a spaceship orbiting planet X discovers that to remain in orbit at From the planet's center,she needs to maintain a speed of What is the mass of planet X? (G = 6.67 × 10-11 N ∙ m2/kg2)

When a spacecraft is launched from the earth toward the sun,at what distance from the earth will the gravitational forces due to the sun and the earth cancel? Earth's mass is 5.97 × 1024 kg,the sun's mass is 1.99 × 1030 kg,and the Earth-sun distance is 1.5 × 1011 m.

What is the gravitational force acting on a 59-kg person due to another 59-kg person standing 2.0 m away? We can model each person as a small sphere.(G = 6.67 × 10-11 N ∙ m2/kg2)

Suppose our sun had 4 times its present mass but the earth orbited it at the same distance as it presently does.What would be the length of the year on the earth under those conditions?

Mithra is an unknown planet that has two moons,A and B,in circular orbits around it.The table summarizes the hypothetical data about these moons.What is the mass of Mithra? (G = 6.67 × 10-11 N ∙ m2/kg2)

Planet Z-34 has a mass equal to one-third that of Earth and a radius equal to one-third that of Earth.With g representing,as usual,the acceleration due to gravity at the surface of Earth,the acceleration due to gravity at the surface of Z-34 is

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars.If gm is the acceleration due to gravity at the surface of Mars,what is the acceleration due to gravity at the location of the satellite?

The reason an astronaut in an earth satellite feels weightless is that

Satellite A has twice the mass of satellite B,and moves at the same orbital distance from Earth as satellite B.Compare the speeds of the two satellites.

If Earth had twice its present mass but it orbited at the same distance from the sun as it does now,its orbital period would be

At a distance of 14,000 km from the center of Planet Z-99,the acceleration due to gravity is 32 m/s².What is the acceleration due to gravity at a point 28,000 km from the center of this planet?

At their closest approach,Venus and Earth are 4.20 × 10¹⁰ m apart.The mass of Venus is 4.87 × 10²⁴ kg,the mass of Earth is 5.97 × 10²⁴ kg,and G = 6.67 × 10^-11 N ∙ m²/kg².What is the magnitude of the gravitational force exerted by Venus on Earth at that point?

As a 70-kg person stands at the seashore gazing at the tides (which are caused by the Moon) ,how large is the gravitational force on that person due to the Moon? The mass of the Moon is 7.35 × 10²² kg,the distance to the Moon is 3.82 × 10⁸ m,and G = 6.67 × 10^-11 N ∙ m²/kg².

By how many newtons does the weight of a 100-kg person decrease when he goes from sea level to mountain top at an altitude of 5000 m? The mean radius of the earth is 6.38 × 10⁶ m.

The captain of a spaceship orbiting planet X discovers that to remain in orbit at From the planet's center,she needs to maintain a speed of What is the mass of planet X? (G = 6.67 × 10^-11 N ∙ m²/kg²)

When a spacecraft is launched from the earth toward the sun,at what distance from the earth will the gravitational forces due to the sun and the earth cancel? Earth's mass is 5.97 × 10²⁴ kg,the sun's mass is 1.99 × 10³⁰ kg,and the Earth-sun distance is 1.5 × 10¹¹ m.

What is the gravitational force acting on a 59-kg person due to another 59-kg person standing 2.0 m away? We can model each person as a small sphere.(G = 6.67 × 10^-11 N ∙ m²/kg²)

Mithra is an unknown planet that has two moons,A and B,in circular orbits around it.The table summarizes the hypothetical data about these moons.What is the mass of Mithra? (G = 6.67 × 10^-11 N ∙ m²/kg²)

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars.If g_m is the acceleration due to gravity at the surface of Mars,what is the acceleration due to gravity at the location of the satellite?