Deck 4: Gravity, Projectiles, and Satellites

Question 1

According to Newton,the closer gravitationally interacting objects are to each other,the

A)less the gravitational force between them.
B)more the gravitational force between them.
C)constancy of the force between them.

Answer 1

B

Question 2

Consider two planets in space that gravitationally attract each other.If the masses of both planets are doubled,and the distance between them doesn't change,then the force between them is

A)one-quarter.
B)half as much.
C)twice as much.
D)four times as much.
E)none of the above

Answer 2

D

Question 3

The Universal Gravitational Constant G was first measured by

A)Galileo.
B)Newton.
C)Cavendish.
D)none of these

Answer 3

C

Question 4

Two objects move toward each other due to gravity.As the objects get closer and closer,the force between them

A)increases.
B)decreases.
C)remains constant.

Question 5

When the distance between a pair of stars doubles,the force between them

A)decreases by one-quarter.
B)decreases by one-half.
C)increases to twice as much.
D)increases to four times as much.
E)stays the same.

Question 6

Compared to other fundamental forces,the Universal Gravitational Constant G indicates gravity to be a relatively

A)weak force.
B)strong force.
C)extremely strong force.

Question 7

According to Newton,the greater the masses of interacting objects,the

A)less the gravitational force between them.
B)greater the gravitational force between them.
C)greater the force between them by the square of the masses.
D)greater the force between them by the square of the distance.

Question 8

According to Newton,the greater the distance between gravitationally interacting objects,the

A)less the gravitational force between them.
B)more the gravitational force between them.
C)constancy of the force between them.

Question 9

If Earth's mass somehow doubles with no change in its size,and your mass remains the same,your weight

A)also doubles.
B)is quadrupled.
C)remains the same.

Question 10

If the Sun were twice as massive,

A)its pull on the Earth would double.
B)Earth's pull on the Sun would double.
C)both of these
D)none of the above

Question 11

If Earth's mass somehow decreased with no change in its radius,your weight would

A)decrease also.
B)increase.
C)remain the same.

Question 12

When the distance between a pair of stars decreases by half,the force between them

A)decreases by one-quarter.
B)decreases by one-half.
C)increases to twice as much.
D)increases to four times as much.
E)stays the same.

Question 13

Newton discovered

A)gravity.
B)that gravity is universal.
C)neither of these

Question 14

Two objects move toward each other due to gravity.As the objects get closer and closer,the acceleration of each

A)increases.
B)decreases.
C)is not affected.

Question 15

Why doesn't the Moon fall toward Earth like apples do?

A)the great distance of the Moon prevents falling
B)moon's small mass prevents falling
C)moon does fall but its great distance keeps it from getting closer
D)moon does fall but due to its tangential motion it also falls around Earth

Question 16

An object is placed exactly halfway between the Earth and the Moon.The object will fall toward the

A)Earth.
B)Moon.
C)neither

Question 17

If your mass doubles,your weight

A)also doubles.
B)is quadrupled.
C)remains the same.

Question 18

Consider two planets in space that gravitationally attract each other.If the mass of one planet is doubled,and the distance between them doesn't change,then the force between them is

A)one-quarter.
B)half as much.
C)twice as much.
D)four times as much.
E)none of the above

Question 19

What is the force of gravity on a 500-N woman standing on Earth's surface?

A)50 N
B)250 N
C)500 N
D)598 N
E)5000 N

Question 20

If the radius of the Earth somehow decreased with no change in mass,your weight would

A)decrease.
B)increase.
C)not change.

Question 21

Inside a freely-falling elevator you would have no

A)gravitational force on you.
B)weight.
C)both of these
D)none of the above

Question 22

The amount of gravitational force that acts on a space vehicle that orbits Earth is

A)nearly zero.
B)nearly as much as the vehicle's weight on Earth's surface.
C)the same as the vehicle's weight on Earth's surface.

Question 23

The planet Jupiter is about 300 times as massive as Earth,yet on its surface you would weigh only about 3 times as much because

A)your mass is 100 times less on Jupiter.
B)Jupiter is significantly farther from the Sun.
C)Jupiter's radius is 10 times Earth's radius.
D)you are 100 times more weightless there.
E)none of the above

Question 24

If the masses of two planets doubles and the distance between them reduces by half,the force between them would be

A)unchanged.
B)half as much.
C)twice as much.
D)four times as much.
E)none of the above

Question 25

How far away from Earth must one travel to completely be beyond Earth's gravity?

A)to a region above the Earth's atmosphere
B)to a region well beyond the Moon
C)to a region beyond the solar system
D)forget it; you can't travel far enough

Question 26

Your weight is defined to be the force

A)due to gravity only.
B)you exert against a supporting surface.
C)equal to your normal force on any surface.

Question 27

If the masses of two planets doubles and the distance between them also doubles,the force between them would be

A)one-quarter.
B)half as much.
C)twice as much.
D)four times as much.
E)none of the above

Question 28

At some point between Earth and the Moon,the forces due to gravity on a space traveler would be the same when this point is

A)nearer Earth.
B)nearer the Moon.
C)mid-way between Earth and the Moon.
D)none of the above

Question 29

Phil stands at rest with both feet on a scale that reads 500 N.After he gently lifts one foot,the scale reads

A)less than 500 N.
B)500 N.
C)more than 500 N.

Question 30

Your weight is equal to mg when you are

A)firmly supported on a horizontal surface and in equilibrium.
B)in Earth's gravitational field.
C)anywhere except in Earth's orbit.
D)all of the above

Question 31

If the radius of the Earth somehow increased with no change in mass,your weight would

A)increase.
B)not change.
C)decrease.

Question 32

An object is placed exactly halfway between the Earth and the Moon.The object will fall toward the

A)Earth.
B)Moon.
C)neither

Question 33

Each of us weighs slightly less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the

A)gravitational force is shielded inside the building.
B)mass of the building attracts us upward slightly.
C)both of these
D)none of the above

Question 34

The force of gravity acts on all apples on an apple tree.Some apples are twice as far from the ground.Such twice-as-high apples of the same mass,have

A)1/4 the weight.
B)1/2 the weight.
C)practically the same weight.

Question 35

A very massive object A and a less massive object B move toward each other under the influence of gravity.Which force,if either,is greater?

A)the force on A
B)the force on B
C)both forces on each other are the same

Question 36

If Earth's mass decreased to one-half its original mass with no change in radius,your weight would

A)decrease to one-quarter.
B)decrease to one-half.
C)remain the same.
D)none of the above

Question 37

A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface.What is her weight there?

A)zero
B)100 N
C)200 N
D)400 N
E)none of the above

Question 38

A supplier wants to make a profit by buying gold by weight at one altitude and selling it at the same price per newton at another altitude.The supplier should

A)buy at a high altitude and sell at a low altitude.
B)buy at a low altitude and sell at a high altitude.
C)disregard altitude because it makes no difference.

Question 39

Inside a freely-falling elevator your

A)acceleration is zero.
B)weight is zero.
C)gravitational interaction with Earth is zero.
D)all the above
E)none of the above

Question 40

In the vacuum of outer space far from our Sun,there is no

A)gravity.
B)atmospheric pressure.
C)both of these
D)none of the above

Question 41

Occupants of the International Space Station experience weightlessness due to

A)the absence of Earth gravity at that altitude.
B)the absence of a support force.
C)rotation of the station.
D)no inertia in space.

Question 42

With no air resistance a projectile fired horizontally maintains its horizontal component of velocity because

A)no forces act on it.
B)no horizontal forces act on it.
C)of no initial vertical component of velocity.
D)all of the above
E)none of the above

Question 43

Perturbations of planets are due to

A)interplanetary forces.
B)deviations from straight-line paths.
C)uneven masses of planets.
D)none of the above

Question 44

As a bowling ball that rolls off the edge of a table falls,its horizontal component of motion

A)decreases.
B)remains constant.
C)increases.

Question 45

Dwarf planet Pluto was discovered by perturbations of

A)Jupiter.
B)Saturn.
C)Uranus and Neptune.
D)all of the above

Question 46

As a bowling ball that rolls off the edge of a table falls,its vertical component of motion

A)decreases.
B)remains constant.
C)increases.

Question 47

You experience weightlessness

A)in the absence of a supporting surface.
B)momentarily when you step off a chair.
C)in a freely falling elevator.
D)all of the above

Question 48

You can experience weight

A)standing on Earth's surface.
B)in an accelerating elevator away from Earth.
C)in a rotating habitat in space.
D)all of the above

Question 49

The identities of dark energy and dark matter are

A)unknown at this time.
B)subjects of intense astronomical interest.
C)both of these
D)neither of these

Question 50

This chapter states a link between Newton's Universal Law of Gravity and

A)biological processes.
B)chemical processes.
C)geological processes.
D)the U.S.Constitution.
E)none of the above

Question 51

The planet Neptune was discovered by perturbations of

A)Uranus.
B)its moons.
C)Pluto.
D)none of the above

Question 52

A dropped ball gains speed because

A)its velocity changes.
B)a gravitational force acts on it.
C)of inertia.
D)its nature is to become closer to Earth.

Question 53

An outcome of universal gravitation is that

A)planets aren't cubes with sharp corners.
B)its discovery prompted other laws of nature.
C)it provided prediction and discovery of planets.
D)all of the above

Question 54

Wobbles in the path of Uranus led to the discovery of

A)Jupiter.
B)Mars.
C)Neptune.
D)all of the above
E)none of the above

Question 55

Planets wobble in their orbits due to

A)the gravitational attraction to other planets.
B)uncertainties in the inverse-square law.
C)elliptical-orbit quirks.
D)all of the above
E)none of the above

Question 56

Strictly speaking,when you step off a curb you are momentarily

A)in orbit.
B)weightless.
C)in space.

Question 57

Weight can be simulated in a space vehicle if the vehicle is

A)falling.
B)in a circular orbit about Earth.
C)rotating.
D)none of the above

Question 58

The Sun is spherical due to

A)Earth circling it.
B)Earth and Moon circling it.
C)gravitation.
D)none of the above

Question 59

Passengers in a high-flying jumbo jet feel their normal weight in flight,whereas passengers in an orbiting space vehicle do not because they are

A)beyond the main pull of Earth's gravity.
B)above the Earth's atmosphere.
C)without support forces.
D)all the above
E)none of the above

Question 60

A bullet fired from a rifle begins to fall

A)as soon as it leaves the barrel.
B)after air friction reduces its speed.
C)neither of these

Question 61

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower.Neglecting air resistance,how far downrange will the bullet be 1 s later?

A)50 m
B)98 m
C)100 m
D)500 m
E)none of the above

Question 62

Two projectiles are fired at equal speeds but different angles.One is fired at an angle of 30° and the other at 60°.With no air resistance,the projectile to hit the ground first will be the one fired at

A)30°.
B)60°.
C)both hit at the same time

Question 63

A rock is thrown upward at 50° with respect to the horizontal.As it rises,its horizontal component of velocity

A)increases.
B)remains unchanged.
C)decreases.

Question 64

Nellie tosses a ball upward at an angle.Assuming no air resistance,which component of velocity changes with time?

A)the horizontal component
B)the vertical component
C)both of these
D)neither of these

Question 65

A projectile is launched straight upward at 50 m/s.Neglecting air resistance its speed upon returning to its starting point is

A)less than 50 m/s.
B)50 m/s.
C)more than 50 m/s.

Question 66

A ball rolls off the edge of a table at the same time another ball drops vertically from the same table.The ball to hit the floor first is the

A)rolling ball.
B)dropped ball.
C)both hit at the same time

Question 67

A projectile is launched at an angle of 15° above the horizontal and lands downrange.With no air resistance,what other projection angle for the same speed would produce the same downrange distance?

A)30°
B)45°
C)50°
D)75°
E)90°

Question 68

A hunter aims a rifle at an angle of 10° below the horizontal.The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle.The bullet to hit the ground first is

A)the dropped one.
B)the fired one.
C)both hit at the same time

Question 69

A bullet fired horizontally hits the ground in 0.5 s.If it had been fired with twice the velocity it would have hit the ground in

A)less than 0.5 s.
B)more than 0.5 s.
C)0.5 s.

Question 70

If a projectile is fired straight up at a speed of 10 m/s,neglecting air resistance,the total time to return to its starting position is

A)1 s.
B)2 s.
C)10 s.
D)20 s.
E)not enough information

Question 71

A rock is thrown upward at 50° with respect to the horizontal.As it rises,its vertical component of velocity

A)increases.
B)remains unchanged.
C)decreases.

Question 72

An object is thrown vertically into the air.Because of air resistance,the time for its descent will be

A)longer than the ascent time.
B)shorter than the ascent time.
C)equal to the ascent time.
D)not enough information

Question 73

A hunter aims a rifle at an angle of 10° above the horizontal.The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle.The bullet to hit the ground first is

A)the dropped one.
B)the fired one.
C)both hit at the same time

Question 74

With no air resistance,a projectile fired at 60° has the same range as if it were fired at

A)15°.
B)30°.
C)45°.
D)75°.

Question 75

One second after a ball rolls off the edge of a horizontal surface at a speed of 10 m/s,

A)its vertical component of velocity is 10 m/s.
B)its speed is about 14 m/s.
C)both of these
D)none of the above

Question 76

A stone is thrown horizontally from the top of a cliff.One second after leaving your hand it drops a vertical distance of

A)5 m.
B)10 m.
C)15 m.

Question 77

Neglecting air resistance,after a ball leaves your hand when you toss it upward,the force on it

A)gradually decreases until the ball reaches the top of its path.
B)first acts upward and then downward after reaching the top.
C)is only the force due to gravity,always directed downward.
D)none of the above

Question 78

If a projectile is fired straight up at a speed of 10 m/s,neglecting air resistance,the time it takes to reach the top of its path is

A)1 s.
B)2 s.
C)10 s.
D)not enough information

Question 79

A hunter fires a bullet from a horizontally-held rifle while simultaneously dropping another bullet from the side of the rifle.The bullet to hit the ground first is

A)the dropped one.
B)the fired one.
C)both hit at the same time

Question 80

With no air resistance,a projectile fired at 50° has the same range as if it were fired at

A)40°.
B)45°.
C)55°.
D)60°.