Deck 2: Newtons Laws

Question 1

As an object moves faster through the air,its terminal speed increases.

Answer 1

False

Question 2

You throw a ball straight up,it peaks out and then comes back down to you.During this motion,the velocity and acceleration always point in the same direction.

Answer 2

False

Question 3

The velocity points down.

Answer 3

False

Question 4

The weight of an object equals its mass times the acceleration of gravity.

Question 5

The acceleration is zero.

Question 6

"Net force" means the vector sum of all the individual forces acting on a particular body.

Question 7

When a car goes around a curve of smaller and smaller radius,the centripetal force on it decreases.

Question 8

As a projectile moves its speed stays constant while its direction changes.

Question 9

You roll a ball off a table and at the same time drop a second ball straight down from the edge of the table.The second ball reaches the ground before the first ball.

Question 10

The net force on the body has its largest magnitude.

Question 11

When a body moves with uniform acceleration,the net force on it is zero.

Question 12

The net force points downward.

Question 13

The displacement vector from the equilibrium position has its largest magnitude.

Question 14

You are presently exerting a gravitational force on the Earth.

Question 15

All forces have specific directions associated with them.

Question 16

When an object reaches its terminal speed,its acceleration is zero.

Question 17

At the peak of its motion,the acceleration of a projectile is zero.

Question 18

With a fixed force,you will impart the same acceleration to a body on the Earth and on the Moon.

Question 19

During its entire motion,the acceleration of a projectile is always g.

Question 20

When a car goes around a curve at twice the speed,the centripetal force on the car doubles.

Question 21

A body on the surface of the Earth weighs 400 lb.The radius of the Earth is about 4,000 miles.If this same body were placed on a 4,000-mile high tower,its weight would be 200 lb.

Question 22

As you go higher and higher above the surface of the Earth,the mass of a body stays constant.

Question 23

If a body were in orbit very near the surface of the Earth,its centripetal acceleration would be equal to g.

Question 24

A ball on a string is being whirled around overhead when the string breaks.The ball will move in the direction of the centripetal force the moment the string breaks.

Question 25

A satellite orbiting the Earth in a circular orbit at 400 miles from the center of Earth is moved to a distance of 1,200 miles from the center of Earth.The gravitational force between the Earth and satellite changes by a factor of 3.

Question 26

Planetary orbits are circles.

Question 27

The displacement vector from the equilibrium position points up.

Question 28

As you go from a point where a gravitational field is strong to a point where the gravitational field gets weaker,the gravitational field lines get farther apart.

Question 29

Gravity acts over a limited distance range.

Question 30

An aircraft weighing 1,500 N has a mass of 153 kg.

Question 31

Just above the surface of the Earth,the direction of the gravitational field is away from the Earth.

Question 32

You push on a wall,and the wall pushes back on you with the same force.This is an example of Newton's third law.

Question 33

Tides are caused because different parts of the Earth's oceans are at different distances from the Moon.

Question 34

As an artillery shell travels from the gun to the target,the projectile's vertical speed changes,but its horizontal speed stays constant.

Question 35

The direction of a field line at a point in space shows the direction of the force that would act on a body placed at the point.

Question 36

When a body moves in a straight line with increasing speed,the net force on it must be increasing.

Question 37

To hold a 5 lb bag of sugar in your hand,you must push upwards on it with a force of 5 lb.This is an example of Newton's third law.

Question 38

A newton is larger than a pound.

Question 39

When you jump,you accelerate upward because the floor exerts an upward force on you.

Question 40

An aircraft weighing 1,500 N is accelerated at 15 m/s²,the force acting on the aircraft is 2,295.9 N.

Question 41

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
The elevator is accelerating upwards at 2 ft/s².

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 42

You whirl a 2-kg body attached to a 1-meter cord around your head in a nearly horizontal circle with a speed of 4 m/s.The tension in the cord is

A)2 N.
B)4 N.
C)8 N.
D)16 N.
E)32 N.

Question 43

Two forces of 4 N and 12 N act on a body simultaneously.The net force on the body is

A)4 N.
B)12 N.
C)16 N.
D)8 N.
E)impossible to tell from the given information.

Question 44

Which is larger,a newton or a pound?

A)a newton
B)a pound
C)This question is nonsense-they don't measure the same physical quantity.
D)They are the same size.

Question 45

The force needed to make an object move in a circle is

A)centripetal force.
B)weight.
C)kinetic friction.
D)static friction.
E)none of the above.

Question 46

If object A has more mass than object B,

A)A will weigh more than B.
B)A will be harder to accelerate than B.
C)A will be harder to keep moving in a circle.
D)all of the above

Question 47

When a freely falling object reaches its terminal speed,

A)it is still accelerating.
B)its acceleration is zero.
C)it is decelerating.
D)its acceleration cannot be determined.

Question 48

The force that keeps your feet from sliding as you walk is

A)centripetal force.
B)weight.
C)kinetic friction.
D)static friction.
E)none of the above.

Question 49

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
The elevator accelerates upwards and is now moving at a constant speed.

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 50

A car moving at a constant speed goes around a curve of 400-ft radius and then goes around a second curve of 200-ft radius.The centripetal force acting on the car as it goes around the 200-ft radius curve is ___________ the value of the centripetal force acting on the car as it goes around the 400-ft radius curve.

A)one quarter
B)one half
C)the same as
D)twice
E)four times

Question 51

If the net force on an object is zero,

A)there must be no forces acting on the object.
B)the object must be at rest.
C)the object's acceleration must be zero.
D)there can be no friction acting on the object.

Question 52

The SI units of acceleration are

A)mi/h.
B)km/h.
C)m/s.
D)m/s².
E)none of the above

Question 53

You push on a block on frictionless ice with a force of 8 N,causing it to accelerate at 2 m/s².The mass of the block is

A)2 kg.
B)4 kg.
C)8 kg.
D)16 kg.
E)6 kg.

Question 54

An example of an action at a distance force is

A)tension.
B)weight.
C)static friction.
D)kinetic friction.
E)none of the above

Question 55

The frequency of a body oscillating from a spring on the Moon is___________ the frequency of the same body oscillating from the same spring on Earth.

A)the same as
B)larger than
C)smaller than
D)not related to
E)depending on the mass,smaller or larger than

Question 56

The acceleration of a body is

A)always in the same direction as its velocity.
B)always in the same direction as the net force on the body.
C)in the direction that the body is moving.
D)equal to the net force on the body.
E)none of the above.

Question 57

The SI units of velocity are

A)mi/h.
B)km/h.
C)m/s².
D)m/s.
E)none of the above

Question 58

You roll a ball off a table and at the same time drop a second ball straight down from the edge of table.The second ball reaches the ground ____________ the first ball reaches the ground.

A)before
B)at the same time that
C)after
D)before or after,depending on the masses,
E)cannot be determined

Question 59

Two identical cars are traveling around the same curve on a highway.One of them is moving at 60 mph,and the other is moving at 30 mph.The centripetal force acting on the car moving at 60 mph is __________ the value of the centripetal force acting on the car moving at 30 mph.

A)one quarter
B)one half
C)the same as
D)twice
E)four times

Question 60

Starting from rest,a 2-kg body acquires a speed of 8 m/s in 2 seconds.The net force acting on the body is

A)2 N.
B)4 N.
C)8 N.
D)16 N.
E)6 N.

Question 61

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
The elevator cable breaks.

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 62

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
After moving downwards at constant speed,the elevator is slowing down at 2 m/s² as it is coming to rest.

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 63

At the highest point on the path of a projectile,its vertical acceleration

A)equals g pointing downwards.
B)equals g pointing upwards.
C)is zero.
D)is undetermined.
E)does not exist.

Question 64

Where is the Sun located relative to a planet's orbit about it?

A)at the center of the orbit,which is a circle
B)at the center of the orbit,which is an ellipse
C)at one focus of the ellipse which forms the orbit
D)none of the above

Question 65

You throw a ball straight up,it peaks out,and then comes back down to you.During this motion,the velocity and acceleration

A)always point in the same direction.
B)always point opposite to each other.
C)sometimes point in the same direction,and other times point opposite to each other.
D)depend on the way the ball is thrown.
E)depend on the mass of the ball.

Question 66

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
The elevator is accelerating downwards at 2 ft/s².

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 67

The horizontal speed of a projectile

A)is zero.
B)stays constant.
C)continuously increases.
D)continuously decreases.
E)sometimes decreases and sometimes increases.

Question 68

As a body falls through air starting from rest,its velocity

A)stays constant.
B)continuously decreases.
C)continuously increases.
D)gets larger and larger,eventually reaching a constant value.
E)gets smaller and smaller,eventually approaching zero.

Question 69

For this situation, I push on a heavy chair.
Suppose I push very hard on the chair,and this time the chair moves and I slip backward as well.Then the strength of the force the chair exerts on me is

A)less than the force I exert on the chair.
B)equal to the force I exert on the chair.
C)greater than the force I exert on the chair.
D)zero.

Question 70

A body is oscillating up and down at the end of a spring. Let’s consider when the body is at the top of its up-and-down motion.
The velocity

A)is zero.
B)has its largest magnitude.
C)points up.
D)points down.

Question 71

For this situation, I push on a heavy chair.
Suppose I push moderately on the chair,and this time the chair does move.Then the strength of the force the chair exerts on me is

A)less than the force I exert on the chair.
B)equal to the force I exert on the chair.
C)greater than the force I exert on the chair.
D)zero.

Question 72

The vertical acceleration of a projectile

A)equals g pointing downwards.
B)equals g pointing upwards.
C)equals g pointing sometimes upwards and other times downwards.
D)is zero.
E)continuously increases.

Question 73

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
The elevator accelerates downwards and is now moving at a constant speed.

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 74

A 160 lb person has a mass of 160/32 = 5 slugs.A 160-lb person steps into an elevator and stands on a bathroom scale.Determine the scale reading for the given scenarios.
After moving upwards at constant speed,the elevator is slowing down at 2 m/s² as it is coming to rest.

A)150 lb
B)160 lb
C)170 lb
D)none of the above

Question 75

The horizontal acceleration of a projectile

A)is zero.
B)stays constant.
C)continuously increases.
D)continuously decreases.
E)sometimes decreases and sometimes increases.

Question 76

The vertical speed of a projectile

A)is zero.
B)stays constant.
C)continuously increases.
D)continuously decreases.
E)sometimes decreases and sometimes increases.

Question 77

Planetary orbits are

A)parabolas.
B)ellipses.
C)circles.
D)none of the above.

Question 78

As a body falls through air starting from rest,its acceleration

A)is zero.
B)stays constant.
C)continuously decreases.
D)continuously increases.
E)gets smaller and smaller,eventually approaching zero.

Question 79

Two cars crash head on.At any given time during the crash,the magnitudes of the collision forces exerted on each car are exactly equal.This is an example of Newton's

A)first law.
B)second law.
C)third law.
D)no law.

Question 80

For this situation, I push on a heavy chair.
Suppose I push lightly on the chair,and the chair doesn't move at all.Then the strength of the force the chair exerts on me is

A)less than the force I exert on the chair.
B)equal to the force I exert on the chair.
C)greater than the force I exert on the chair.
D)zero.