Deck 10: Projectile and Satellite Motion

Question 1

A bullet fired horizontally 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

Answer 1

as soon as it leaves the barrel.

Question 2

A projectile is launched at ground level an angle of 15 degrees above the horizontal and lands down range.What other projection angle for the same speed would produce the same down-range distance?

A)30 degrees
B)45 degrees
C)50 degrees
D)75 degrees
E)90 degrees

Answer 2

75 degrees

Question 3

A hunter on level ground fires a bullet at an angle of 2 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle.Which bullet will hit the ground first?

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

Answer 3

the fired one

Question 4

Which of the following is not a vector quantity?

A)velocity
B)speed
C)acceleration
D)None are vector quantities.
E)All are vector quantities.

Question 5

Throw an object upward at a 45 degree angle.With no gravity it will follow a straight-line path.But because of gravity,at the end of 1 second,it is

A)about 5 m below the straight line.
B)about 10 m below the straight line.
C)about 15 m below the straight line.

Question 6

According to Kepler's laws,the paths of planets about the sun are

A)parabolas.
B)circles.
C)straight lines.
D)ellipses.
E)none of these

Question 7

An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a ground speed of

A)0 km/h.
B)100 km/h.
C)141 km/h.
D)200 km/h.

Question 8

Both Newton and Kepler considered forces on the planets.Kepler hypothesized the direction of the forces was

A)along their directions of travel.
B)toward the sun.
C)neither

Question 9

Roll a bowling ball off the edge of a table.As it falls,its horizontal component of velocity

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

Question 10

A projectile is launched vertically upward at 50 m/s.If air resistance is negligible,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 11

A stone is thrown horizontally from the top of a cliff.One second after it has left your hand,its vertical distance below the top of the cliff is

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

Question 12

Use the following figure to answer the question :

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

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

Question 13

An Earth satellite is simply a projectile

A)freely falling around the Earth.
B)floating motionless in space near the Earth.
C)approaching the Earth from outer space.

Question 14

Earth satellites are typically more than 100 km high so as to be above the Earth's

A)atmosphere.
B)gravitational field.
C)both of these

Question 15

A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle.Which bullet will hit the ground first?

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

Question 16

Use the following figure to answer the question :

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

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

Question 17

A bullet fired horizontally over level ground hits the ground in 0.5 second.If it had been fired with twice the speed in the same direction,it would have hit the ground in

A)less than 0.5 s.
B)more than 0.5 s.
C)0)5 s.

Question 18

A projectile is fired horizontally in a region of no air resistance.The projectile maintains its horizontal component of velocity because

A)it is not acted on by any forces.
B)it is not acted on by any horizontal forces.
C)it has no vertical component of velocity to begin with.
D)the net force acting on it is zero.
E)none of these

Question 19

An object is dropped and freely falls to the ground with an acceleration of 1 g.If it is thrown upward at an angle instead,its acceleration will be

A)0 g.
B)1 g downward.
C)1 g upward.
D)larger than 1 g.
E)none of these

Question 20

An airplane travels at 141 km/h toward the northeast.What is its component of velocity due north?

A)41 km/h
B)100 km/h
C)110 km/h
D)141 km/h

Question 21

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 given to say.

Question 22

Acceleration due to gravity on the moon is less than on Earth,and the moon is smaller than Earth.So compared to an Earth satellite,a satellite in close orbit about the moon would travel

A)faster.
B)slower.
C)the same.
D)Not enough information is given to say.

Question 23

A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground.The player sees the ball land 20 m down range.What is the player's pitching speed?

A)about 5 m/s
B)about 10 m/s
C)about 20 m/s
D)about 25 m/s
E)none of these

Question 24

A river 100 m wide flows due south.A boat that goes 1 m/s relative to the water is pointed due east as it crosses from the west bank.The boat crosses in

A)50 s.
B)100 s.
C)141 s.
D)200 s.

Question 25

The tangential velocity of an Earth satellite is its velocity

A)parallel to the surface of the Earth.
B)perpendicular to the surface of the Earth.
C)attributed to satellites moving in any direction.

Question 26

An airplane flies at 40 m/s at an altitude of 50 meters.The pilot drops a heavy package which falls to the ground.Where,approximately,does the package land relative to the plane's new position?

A)beneath the plane
B)400 m behind the plane
C)500 m behind the plane
D)more than 500 m behind the plane
E)none of these

Question 27

A projectile is fired vertically from the surface of the Earth at 8 km/s.The projectile will

A)go into circular orbit about the Earth.
B)rise and fall back to the Earth's surface.
C)follow an uncertain path.
D)escape from the Earth.

Question 28

A river 100 m wide flows due south.A boat that goes 1 m/s relative to the water is pointed due east as it crosses from the west bank.Relative to the Earth,the boat travels

A)nowhere.
B)141 m.
C)100 m.
D)200 m.
E)241 m.

Question 29

Without air resistance,a projectile fired horizontally at 8 km/s from atop a mountain would

A)accelerate downward at g as it moves horizontally.
B)trace a curve that matches the earth's curvature.
C)return later to its starting position and repeat its falling behavior.
D)all of these
E)none of these

Question 30

A river 100 m wide flows due south at 1 m/s.A boat that goes 1 m/s relative to the water leaves the west bank.To land at a point due east of its starting point,the boat must be pointed

A)northeast.
B)east.
C)southeast.
D)nowhere-it can't be done.

Question 31

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 second later?

A)50 m
B)98
C)100
D)490
E)none of these

Question 32

If a satellite's radial velocity is zero at all times,its orbit must be

A)parabolic.
B)elliptical.
C)circular.
D)geosynchronous.

Question 33

The radial velocity of an Earth satellite is its velocity

A)parallel to the surface of the Earth.
B)perpendicular to the surface of the Earth.
C)attributed to satellites moving in any direction.
D)none of these

Question 34

A projectile is fired into the air at an angle of 50 degrees with the ground and lands on a target that is at the same level at which the projectile started.It will also land on the target if it is fired at an angle of

A)40 degrees.
B)45 degrees.
C)55 degrees.
D)60 degrees.
E)none of these

Question 35

The ground speed of an airplane that has an airspeed of 200 km/h when it is in a 200-km/h crosswind is

A)0 km/h.
B)200 km/h.
C)283 km/h.
D)400 km/h.
E)1600 km/h.

Question 36

Planets would crash into the sun if it weren't for

A)their tangential velocities.
B)their vast distances from the sun.
C)the inverse-square law.
D)their relatively small masses.
E)the fact that they are beyond the main gravitation of the sun.

Question 37

Two projectiles are fired from ground level at equal speeds but different angles.One is fired at an angle of 30 degrees and the other at 60 degrees.The projectile to hit the ground first will be the one fired at (neglect air resistance)

A)30 degrees.
B)60 degrees.
C)Both hit at the same time.

Question 38

After a rock thrown straight up reaches the top of its path and then falls a short distance,its acceleration is (neglect air resistance)

A)greater than when it was at the top of its path.
B)less than when it was at the top of its path.
C)the same as it was at the top of its path.

Question 39

A river 100 m wide flows due south at 1 m/s.A boat that goes 1 m/s relative to the water is pointed due east as it crosses from the west bank.The boat reaches the east bank

A)due east of where it started.
B)141 m farther south than where it started.
C)100 m farther south than where it started.
D)100 m farther north than where it started.

Question 40

A bullet is fired horizontally with an initial velocity of 300 m/s from a tower 20 m high.If air resistance is negligible,the horizontal distance the bullet travels before hitting the ground is about

A)200 m.
B)300 m.
C)400 m.
D)500 m.
E)600 m.

Question 41

Consider a moon that orbits one of our most distant planets in an elliptical path.The distance that the moon covers each day is

A)greatest when the moon is closest to the planet.
B)greatest when the moon is furthest from the planet.
C)the same regardless of its distance from the sun.
D)the same regardless of its distance from the planet.

Question 42

A "weightless" astronaut in an orbiting shuttle is

A)shielded from the Earth's gravitational field.
B)beyond the pull of gravity.
C)pulled only by gravitation to the shuttle which cancels the Earth's gravitational pull.
D)like the shuttle,pulled by Earth's gravitation.
E)none of these

Question 43

The speeds of the planets about the sun depend on

A)their distances from the sun.
B)the masses of the planets.
C)their periods of rotation.
D)None of the above are correct.

Question 44

The circular path of a satellite orbiting the Earth is characterized by a constant

A)speed.
B)acceleration.
C)radial distance.
D)all of these
E)none of these

Question 45

A lunar month is about 28 days.If the moon were closer to the Earth than it is now,the lunar month would be

A)less than 28 days.
B)more than 28 days.
C)unchanged at 28 days.

Question 46

A vertically oriented rocket that is somehow able to maintain a continuous upward velocity of 8 km/s will

A)escape from the Earth.
B)be unable to escape the Earth.
C)eventually maintain a fixed orbit around the sun.

Question 47

Minimal orbital speed about the Earth is about 8 km/s.Minimal orbital speed about the moon would be

A)less than 8 km/s.
B)more than 8 km/s.
C)about 8 km/s.

Question 48

It takes Pluto a longer time to orbit the sun than the Earth does because Pluto

A)has much further to go.
B)goes much slower.
C)Choices A and B are both correct.
D)none of the above

Question 49

A satellite in an elliptical orbit travels at constant

A)velocity.
B)speed.
C)acceleration.
D)all of these
E)none of these

Question 50

The fastest moving planet in a solar system is

A)the smallest planet.
B)the most massive planet.
C)the planet nearest the sun.
D)the planet farthest from the sun.
E)any planet,for they all move at the same speed.

Question 51

Consider a monkey wrench released at rest at the far edge of the solar system.Suppose that it drops to the Earth by virtue of only Earth gravity.It will strike the Earth's surface with a speed of about

A)9)8 m/s.
B)8 km/s.
C)11.2 km/s.
D)the speed of light.

Question 52

A woman on the surface of the Earth has a mass of 50 kilograms and a weight of 490 newtons.If the woman were floating freely inside a space habitat far away from Earth,she would have

A)less weight and more mass.
B)less weight and the same mass.
C)less weight and less mass.
D)more weight and less mass.
E)none of these

Question 53

What prevents satellites such as the space shuttle from falling?

A)gravity
B)centripetal force
C)centrifugal force
D)the absence of air drag
E)Nothing;they are continually falling as they orbit the Earth.

Question 54

A satellite describes an elliptical orbit about a planet.The satellite travels much faster when it is directly over a

A)large ocean.
B)large island.
C)high mountain range.
D)great plain or plateau.
E)None of the above choices affects its speed very much.

Question 55

Minimal orbit speed about the Earth is about 8 km/s.Minimal orbital speed about Jupiter would be

A)less than 8 km/s.
B)more than 8 km/s.
C)about 8 km/s.

Question 56

Our moon travels the fastest as it orbits the Earth when it is

A)performing an eclipse.
B)rotating.
C)revolving.
D)closest.
E)All of the above choices are true.

Question 57

The period of a satellite,the time it takes for a complete revolution,depends on the satellite's

A)mass.
B)weight.
C)radial distance.
D)all of these
E)none of these

Question 58

An Earth satellite is in an elliptical orbit.The satellite travels fastest when it is

A)nearest the Earth.
B)farthest from the Earth.
C)It travels at constant speed everywhere in orbit.

Question 59

A projectile is fired vertically from the surface of the Earth at 5 km/s.The projectile will

A)go into circular about the Earth.
B)go into an elliptical orbit about the Earth.
C)rise and fall back to the Earth's surface.
D)none of these

Question 60

A lunar month is about 28 days.If the moon were farther from the Earth than it is now,the lunar month would be

A)more than 28 days.
B)less than 28 days.
C)about 28 days.
D)difficult to predict without much more information.

Question 61

A rocket coasts in an elliptical orbit about the Earth.To attain escape velocity using the least amount of fuel in a brief firing time,should it fire off at the apogee,or at the perigee? (Hint: Let "Fd = change in KE" guide your thinking. )

A)perigee,where it is closest and fastest
B)apogee,where it is farthest and slowest
C)same either location

Question 62

Pioneer 10 was able to escape the solar system by

A)having a sufficient escape velocity at launch.
B)"bouncing off" Jupiter like a tennis ball bouncing off an approaching tennis racket.
C)refueling via solar cells.
D)nuclear-powered sustained thrust.

Question 63

From Earth,one satellite appears to overtake another.The faster satellite is

A)higher.
B)lower.
C)smaller.
D)can't say

Question 64

Which would require the greater change in the Earth's orbital speed (30 km/s);slowing down so the Earth crashes into the sun,or speeding up so the Earth escapes the sun?

A)slowing down
B)speeding up
C)same each way
D)More information about Earth-sun distance is needed.

Question 65

Angular momentum is conserved for a satellite in

A)circular orbit.
B)elliptical orbit.
C)both of these
D)neither of these

Question 66

Rockets that launch satellites into orbit need less thrust when fired from

A)Cape Canaveral.
B)Edwards Air Force Base in California.
C)Hawaii.
D)Location does not bear on the required rocket thrust.

Question 67

Which would require the greater energy;slowing down of the orbital speed of the Earth so it crashes into the sun,or speeding up the orbital speed of the Earth so it escapes the sun?

A)slowing down
B)speeding up
C)same each way

Question 68

A satellite near the Earth makes a full circle in about an hour and a half.How long would a satellite located as far away as the moon take to orbit the Earth?

A)the same hour and a half
B)less than an hour and a half
C)about 28 days
D)More information about the satellite is needed.
E)none of these

Question 69

Compared to the period of satellites in orbit close to the Earth,the period of satellites in orbit far from the Earth is

A)longer.
B)shorter.
C)the same.
D)not enough information

Question 70

The force of gravity does work on a satellite when it is in

A)circular orbit.
B)elliptical orbit.
C)both of these
D)neither of these

Question 71

Angular momentum is greater for a satellite when it is at the

A)apogee.
B)perigee.
C)same at apogee and perigee

Question 72

Acceleration is greater for a satellite when it is at the

A)apogee.
B)perigee.
C)zenith.
D)same acceleration at all of the above places.

Question 73

The Early Bird communication satellite hovers over the same point on Earth's equator indefinitely.This is because

A)forces other than Earth's gravity act on it.
B)it pulls as hard on the Earth as the earth pulls on it.
C)it is beyond the main pull of Earth gravity.
D)it is kept aloft by ground control.
E)its orbital period is 24 hours.

Question 74

Communications and weather satellites always appear at the same place in the sky.This is because these satellites are

A)beyond the pull of the Earth's gravitational field.
B)moving at a speed just short of escape velocity.
C)orbiting the Earth with a 24-hour period.
D)stationary in space.
E)none of these