Universal Gravitation

b

41. If Earth was twice its present mass, but its size was not changed, you would weigh a. half as much b. twice as much c. four times as much d. one-quarter as much e. the same amount

first half of smile

Describe this graph: Which of the following graphs best illustrates the relationship between a satellite's orbital radius ro and its orbital speed v?

first half of smile

Describe this graph: Which of the following graphs best illustrates the relationship between a satellite's orbital speed vo and its orbital radius ro?

straight diagonal line up and right

Describe this graph: Which of the following graphs best represents the relationship between the gravitational force, F, that Earth exerts and the mass, m, of an object sitting at Earth's surface, that the force is exerted upon?

b

If Earth was twice its present mass, but its size was not changed, you would weigh a. half as much b. twice as much c. four times as much d. one-quarter as much e. the same amount

c

If Earth's mass was four times what it is presently, what would its radius have to be (comparably) so that the gravitational field strength at its surface would remain 9.8 N/kg? a. one-half as large b. one-quarter as large c. twice as large d. four times larger e. the same size

a

Objects onboard an orbiting space station appear to be "floating" because a. they're falling together b. they're weightless c. they're outside Earth's gravitational pull d. they're in the vacuum of space e. they're in the gravitational field of the Moon

e

What is the magnitude of the gravitational force acting on a 79.5-kg student due to a 60.0-kg student sitting 2.25 m away in the lecture hall? A) 3.14 x 10-9 N B) 2.82 x 10-8 N C) 7.91 x 10-10 N D) 1.41 x 10-7 N E) 6.29 x 10-8 N

c

What is the weight of a 2.50-kg bag of sand on the surface of the earth? A. 2.50 N B. 9.80 N C. 24.5 N D. 49.0 N E. 98.0 N

c

What would the gravitational field strength be on a planet with half Earth's mass and half its radius? a. 78.4 N/kg b. 39.2 N/kg c. 19.6 N/kg d. 9.8 N/kg e. 4.9 N/kg

e

What would the gravitational field strength be on a planet with twice Earth's mass and twice its radius? a. 78.4 N/kg b. 39.2 N/kg c. 19.6 N/kg d. 9.8 N/kg e. 4.9 N/kg

b

Which of the following statements concerning gravitational fields is true? a. Only very massive objects have gravitational fields. b. The gravitational field strength of an object is one-quarter as great at twice the distance from the object's centre. c. The strength of an object's gravitational field is inversely proportional to its mass. d. The strength of an object's gravitational field is inversely proportional to the square of its mass. e. The strength of an object's gravitational field is inversely proportional to the distance from the object's centre.

a

Which of the following statements concerning gravitational fields is true? a. The strength of an object's gravitational field varies inversely as the square of the distance to its centre. b. The strength of an object's gravitational field varies directly as the square of its mass. c. The Moon's gravitational field is much smaller than Earth's because the Moon's radius is so much smaller than Earth's. d. An object's mass alone dictates the strength of the gravitational field at its surface. e. An object's size alone dictates the strength of its gravitational field.

c

Which one of the following statements concerning the two "gravitational constants" G, the universal gravitational constant, and g the magnitude of the acceleration due to gravity is true? A. The values of g and G do not depend on location. B. The values of g and G depend on location. C. The value of G is the same everywhere in the universe, but the value of g is not. D. The value of g is the same everywhere in the universe, but the value of G is not. E. The values of g and G are equal on the surface of any planet, but in general, vary with location in the universe

b

Which statement best explains why the weight of an object of mass m is different on Mars than it is on the Earth? A. The mass of Mars is different from that of Earth. B. The masses and radii of Mars and Earth are not the same. C. The mass m is further from the Earth's center when it is on Mars. D. The constant G is different on Mars. E. The mass m will be different on Mars.

t

T/F - An object in orbit around the Earth only appears weightless when it is actually fre falling with everything around it

t

T/f - An object's weight depends on the strength of the gravitational field it is in. This varies with latitue, altitude and locally.

F

T/f - If the moon was the twice the distance from the Earth as it is now, the gravitational attraction force between the two bodies would be half as great

b

Two point masses m and M are separated by a distance d. If the distance between the masses is increased to 3d, how does the gravitational force between them change? A) The force will be one-third as great. B) The force will be one-ninth as great. C) The force will be three times as great. D) The force will be nine times as great. E) It is impossible to determine without knowing the numerical values of m, M, and

d

Two satellites of different masses are in the same circular orbit about the earth. Which one of the following statements is true concerning the magnitude of the gravitational force that acts on each of them? A. The magnitude of the gravitational force is zero newtons for both satellites. B. The magnitude of the gravitational force is the same for both satellites, but not zero newtons. C. The magnitude of the gravitational force is zero newtons for one, but not for the other. D. The magnitude of the gravitational force depends on their masses. E. The magnitude of the gravitational force varies from point to point in their orbits.

c

40. If you weighed 112 N on the Moon where g = 1.6 N/kg, how much would you weigh on Earth? a. 1.1 x 10^2 N b. 1.7 x 10^4 N c. 6.9 x 10^2 N d. 1.1 x 10^4 N e. 6.9 x 10^3 N

f, two times

t/f - If Earth's mass and radius were both one half their present values, the acceleration due to gravity on the surface of the Earth would be four times its present value.

f

t/f - If the Moon was twice the distance from Earth as it is now, the gravitational force of attraction between the two bodies would be half as great.

f

t/f - Objects dropped at the equator will fall with greater acceleration than if dropped at one of the poles

f, third

t/f - Of Newton's three laws of motion, Newton's law of universal gravitation is most closely associated with his second law of motion

d

28/ The acceleration due to gravity on the surface of a planet having twice the Earth's mass and twice its radius would be a. 39.2 m/s2 b. 19.6 m/s2 c. 9.8 m/s2 d. 4.9 m/s2 e. 2.45 m/s2

b

29. Planet X has a radius 4 times that of Earth and the acceleration due to gravity at the surface of planet X is 4.9 m/s2. The mass of Planet X compared to Earth's mass is a. 16 times b. 8 times c. 4 times d. 2 times e. the same

b

3. A satellite orbiting the earth is experiencing a force of gravity due to the earth's gravitational pull. A second satellite is orbiting the Earth with 0.5 times the mass of the first satellite and a distance from the earth's centre that is twice as great. The force of gravity on the first satellite compared t the second satellite is: a. 16 times b. 8 times c. 4 times d. 2 times e. the same

b

31. With all other things being equal, had the value of the universal gravitational constant been twice its present value, your weight would be a. four times as great b. two times as great c. the same d. one-half as great e. one-quarter as great

b

33. The force of gravity acting on a 10-kg object at an altitude equivalent to the Earth's radius is a. 49 N b. 24 N c. 9.8 N d. 5.0 N e. 2.4 N

a

34. The orbital radius of a satellite circling the Earth a. depends only on its orbital speed b. depends only on its mass c. depends on both its orbital speed and its mass d. is the same for all satellites e. is directly proportional to its orbital speed

c

35. The orbital speed of a satellite at an altitude equivalent to Earth's radius (rE = 6.38 × 106 m) is (mE = 5.98 × 1024 kg, G = 6.67 × 10-11 N·m2 /kg2) a. 9.8 × 10^3 m/s b. 7.9 × 10^3 m/s d. 4.9 × 10^3 m/s c. 5.6 × 10^3 m/s e. 2.5 × 10^3 m/s

e

37. The gravitational field strength of Earth a. has a value of 9.8 N/kg [down] at all locations on its surface b. is greater at the equator than at the poles c. is smallest at the peak of Mount Everest, the highest elevation d. is largest at the deepest spot on the ocean floor e. is largest at the poles

e

38. How much would a 60-kg person weigh on the Moon where the gravitational field strength has a magnitude of 1.6 N/kg? a. 60 kg b. 96 kg c. 98 kg d. 98 N e. 96 N

b

A marble is dropped straight down from a distance h above the floor. Let Fm = the magnitude of the gravitational force on the marble due to the earth; Fe = the magnitude of the gravitational force on the earth due to the marble; am = the magnitude of the acceleration of the marble toward the earth; ae = the magnitude of the acceleration of the earth toward the marble. Which set of conditions is true as the marble falls toward the earth? A. Fm = Fe and am < ae B. Fm = Fe and am > ae C. Fm < Fe and am = ae D. Fm > Fe and am = ae E. Fm < Fe and am > ae

d

According to Newton's law of universal gravitation, the gravitational force of attraction between two objects would be a. half as strong if they're moved twice as far apart b. twice as strong if they're moved half as far apart c. four times as strong if they're moved twice as far apart d. four times as strong if they're moved half as far apart e. twice as strong if they're moved twice as far apart

a

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the mass of the astronaut in the capsule compare to her mass on the earth? A. It is equal to her mass on earth. B. It is equal to one-half of her mass on earth. C. It is equal to one-third of her mass on earth. D. It is one-fourth her mass on earth. E. It is equal to one-sixteenth her mass on earth.

d

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the weight of the astronaut in the capsule compare to her weight on the earth? A. It is equal to her weight on earth. B. It is equal to one-half of her weight on earth. C. It is equal to one-third of her weight on earth. D. It is one-fourth her weight on earth. E. It is equal to one-sixteenth her weight on earth.

d

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the weight of the astronaut in the capsule compare to her weight on the earth? A) It is equal to her weight on earth. B) It is equal to one-half of her weight on earth. C) It is equal to one-third of her weight on earth. D) It is one-fourth her weight on earth. E) It is equal to one-sixteenth her weight on earth.

e

Astronauts on board an orbiting space station appear to be "floating" because a. they are in the vacuum of space b. they are outside Earth's gravitational influence c. the force of gravity acting on them has been reduced to an insignificant level d. they have become truly "weightless" e. they are in free fall along with the space station itself

a

Consider two planets, A and B. Planet A has half the mass and half the radius of planet B. The ratio of gA : gB would be a. 2 : 1 b. 1 : 2 c. 4 : 1 d. 1 : 4 e. 1 : 1

first half of smile

Describe this graph: The relationship between the gravitational force of attraction, FG, of two objects on one another and their separation distance r is best illustrated by which of the following graphs?

first half of smile

Describe this graph: Which of the following graphs best depicts the relationship between the gravitational force, F, that two masses exert on one another and the distance, d, which separates their centres of mass?

a

Physicsman whose mass is 70 k is in an elevator accelerating upwards at a rate of 2 m/s2. What is his apparent weight? a. 826 N b. 546 N c. 686 N d. 900 N e. 500 N

d

Planet X has a mass 8 times that of Earth and the acceleration due to gravity at its surface is 19.6 m/s2. The radius of planet X compared to Earth is a. 16 times b. 8 times c. 4 times d. 2 times e. the same

d

The person responsible for determining the value of the universal gravitational constant is a. Galileo Galilei b. Isaac Newton c. William Herschel d. Henry Cavendish e. Albert Einstein

d

The value of "g" at the surface of Mars is 3.7 N/kg. How much would a 60.0-kg person weigh at an altitude above the Martian surface equivalent to the planet's radius? a. 2.2 x 10^2 N b. 1.6 x 10^2 N c. 1.1 x 10^2 N d. 56 N e. 28 N

c

The weight of an object in free fall just above Earth's surface is a. zero b. less than normal c. normal d. greater than normal e. almost zero

c

To produce an artificial gravity on board a space station a. would be impossible b. would require an enormous quantity of matter c. is easily achieved by rotating the space station d. would be possible by maintaining an inertial frame of reference e. is purely science fiction

b

Your "weight" is properly defined as a. the amount of material of which you are composed b. the gravitational force which Earth exerts on you c. the gravitational force you exert on Earth d. the force you exert on a set of bathroom scales e. none of the above

b

Your weight on board an orbiting space station would be a. normal b. only slightly less than normal c. much less than normal d. slightly greater than normal e. zero

d

onsider two planets, A and B. Planet A has twice the mass and twice the radius of planet B. The ratio of gA : gB would be a. 1 : 4 b. 4 : 1 c. 1 : 2 d. 2 : 1 e. 1 : 1

t

t/f - If you were sitting half as far from your nearest classmate, the gravitational force of attraction between the two of you would be four times as strong.

t

t/f - All geosynchronous satellites must have the same orbital radius

f

t/f - An object in orbit around Earth is truly weightless.