Deck 4: Newtons Second Law of Motion

Question 1

A bag of groceries that has a mass of 10 kilograms weighs about

A)1 N.
B)10 N.
C)100 N.
D)1000 N.
E)greater than 1000 N.

Answer 1

100 N.

Question 2

If the net force on a cart is tripled, the cart's acceleration

A)is one third.
B)is two thirds.
C)is three times as much.
D)is more than three times as much.

Answer 2

is three times as much.

Question 3

A kilogram is a measure of an object's

A)force.
B)mass.
C)both of these
D)neither of these

Answer 3

mass.

Question 4

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much

A)inertia.
B)mass.
C)volume.
D)all of the above
E)none of the above

Question 5

Compared to the mass of an apple on Earth, the mass of the apple on the Moon is

A)one sixth as much.
B)the same.
C)six times as much.
D)zero.

Question 6

The newton is a unit of

A)force.
B)mass.
C)density.
D)inertia.

Question 7

If an apple experiences a constant net force, it will have a constant

A)velocity.
B)speed.
C)acceleration.
D)position.
E)more than one of the above

Question 8

The mass of a lamb that weights 110 N is about

A)1 kg.
B)11 kg.
C)110 kg.
D)1100 kg.
E)none of the above

Question 9

Whenever the net force on an object is zero, its acceleration

A)may be less than zero.
B)is zero.
C)may be more than zero.

Question 10

Which has the greater mass?

A)a king-size pillow
B)an automobile battery
C)both the same

Question 11

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is

A)more than 10 N.
B)less than 10 N.
C)10 N.

Question 12

A mobile phone is pulled northward by a force of 10 N and at the same time pulled southward by another force of 15 N. The resultant force on the phone is

A)0 N.
B)5 N.
C)25 N.
D)150 N.

Question 13

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same

A)mass.
B)volume.
C)weight.
D)all of the above
E)none of the above

Question 14

A 10-N falling object encounters 10 N of air resistance. The net force on the object is

A)0 N.
B)4 N.
C)6 N.
D)10 N.
E)none of these

Question 15

If you double the net force on an object, you'll double its

A)acceleration.
B)speed.
C)velocity.
D)all the above

Question 16

A 10-N falling object encounters 4 N of air resistance. The net force on the object is

A)0 N.
B)4 N.
C)6 N.
D)10 N.
E)none of the above

Question 17

An object's weight is properly expressed in units of

A)meters.
B)kilograms.
C)newtons.
D)cubic centimeters.

Question 18

A 1-kg mass at the Earth's surface weighs

A)1 N.
B)5 N.
C)10 N.
D)12 N.
E)none of the above

Question 19

The mass of a pet turtle that weighs 10 N is about

A)1 kg.
B)10 kg.
C)100 kg.
D)1000 kg.
E)none of the above

Question 20

A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is

A)30 N.
B)300 N.
C)3000 N.
D)more than 3000 N.

Question 21

Strange as it may seem, it is just as difficult to accelerate a car on a level surface on the Moon as it is here on Earth because

A)the mass of the car is independent of gravity.
B)the weight of the car is independent of gravity.
C)both of these
D)neither of these

Question 22

A heavy ball hangs by a string, with a second string attached to its bottom. A slow pull on the bottom string breaks the

A)top string.
B)bottom string.
C)top or bottom string equally.

Question 23

If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration

A)quadruples.
B)doubles.
C)stays the same.
D)halves.
E)none of these

Question 24

In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the

A)Moon.
B)Earth.
C)planet Jupiter.

Question 25

A heavy block at rest is suspended by a vertical rope. When the block accelerates upward by the rope, the rope tension

A)is less than its weight.
B)equals its weight.
C)is greater than its weight.

Question 26

A car by itself is capable of a certain maximum acceleration. When it tows a car of the same mass, its maximum acceleration is

A)one half.
B)one third.
C)one fourth.
D)the same.
E)none of these

Question 27

You drive your car at a constant 60 km/h along the highway. You apply the brakes until the car slows to 40 km/h. If at that moment you suddenly release the brakes, the car tends to

A)momentarily regain its higher initial speed.
B)continue moving at 40 km/h.
C)decrease in speed if no other forces act.

Question 28

An apple at rest weighs 1 N. The net force on the apple when it is in free fall is

A)0 N.
B)0.1 N.
C)1 N.
D)9.8 N.
E)none of the above

Question 29

At equilibrium on a bathroom weighting scale, the downward pull of gravity on you is balanced by

A)your weight.
B)an upward support force.
C)your mass.

Question 30

Your weight as measured on your bathroom scale is

A)equal to your mass.
B)the force due to gravity on you.
C)a property of mechanical equilibrium.
D)all of the above

Question 31

When you stand at rest with your left foot on one bathroom scale and your right foot on a similar scale, each of the scales will

A)read half your weight.
B)read your weight.
C)show readings that when added equal your weight.
D)cancel your weight.

Question 32

A car by itself is capable of a certain maximum acceleration. When it tows a twice-as-massive car, its maximum acceleration is

A)one half.
B)one third.
C)one fourth.
D)the same.
E)none of these

Question 33

An object with twice as much mass as another object has twice as much

A)inertia.
B)speed.
C)acceleration due to gravity.
D)all of the above

Question 34

Which has zero acceleration? An object

A)at rest.
B)moving at constant velocity.
C)in mechanical equilibrium.
D)all of the above
E)none of the above

Question 35

When the bottom string is pulled slowly in the heavy-ball-and-strings demonstration (Figure 4.8 in your book), tension

A)in the top string is due to your pull plus the weight of the ball.
B)is about the same in both strings.
C)in the bottom string is zero.

Question 36

A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass?

A)the one on Earth
B)the one on the Moon
C)They have the same mass.
D)not enough information

Question 37

A heavy ball hangs by a string, with a second string attached to its bottom (Figure 4.8 in your book). A quick pull on the bottom string breaks the

A)top string.
B)bottom string.
C)top or bottom string equally.

Question 38

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

A)decreases.
B)increases.
C)remains the same.

Question 39

An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is

A)0 N.
B)0.1 N.
C)1 N.
D)9.8 N.
E)none of the above

Question 40

A constant net force on a rail-road car produces constant

A)velocity.
B)acceleration.
C)both of these
D)neither of these

Question 41

When a constant and sustained upward force acts on a rocket, its acceleration increases mainly because

A)gravity becomes weaker with increased distance.
B)the mass of the rocket decreases as fuel is burned.
C)No way, for acceleration would be constant.

Question 42

A push on a 1-kg brick accelerates it. Neglecting friction, equally accelerating a 10-kg brick requires

A)just as much force.
B)10 times as much force.
C)100 times as much force.
D)one-tenth the amount of force.
E)none of the above

Question 43

A 1-kg rock that weighs 10 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is

A)less than 10 N.
B)10 N.
C)more than 10 N.

Question 44

If less horizontal force is applied to a sliding object than is needed to maintain a constant velocity, the object

A)accelerates in the direction of the applied force.
B)experiences decreased friction.
C)eventually slides to a stop.
D)none of the above

Question 45

A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?

A)less than 6 N
B)6 N
C)more than 6 N
D)need more information

Question 46

A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s². What is the mass of the car?

A)500 kg
B)1000 kg
C)1500 kg
D)3000 kg
E)none of these

Question 47

A 10-N block and a 1-N block lie on a horizontal frictionless table. To impart equal horizontal accelerations, we would have to push the heavier block with

A)an equal force.
B)10 times as much force.
C)10 squared or 100 times as much force.
D)1/10 as much force.
E)none of the above

Question 48

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity, the object

A)accelerates in the direction of the applied force.
B)accelerates opposite the direction of the applied force.
C)experiences greater friction.
D)none of the above

Question 49

A boulder following a straight-line path at constant velocity has

A)a net force acting upon it in the direction of motion.
B)zero acceleration.
C)no forces acting on it.
D)none of the above

Question 50

The force required to maintain a constant velocity for an astronaut in free space is equal to

A)zero.
B)the mass of the astronaut.
C)the weight of the astronaut.
D)the force required to stop the astronaut.
E)none of the above

Question 51

A car has a mass of 1000 kg and accelerates at 2 m/s². What net force is exerted on the car?

A)500 N
B)1000 N
C)1500 N
D)2000 N
E)none of these

Question 52

Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom

A)before the small block.
B)after the small block.
C)at the same time as the small block.

Question 53

If a non-rotating object has no acceleration, then we can say for certain that it is

A)at rest.
B)moving at constant non-zero velocity.
C)in mechanical equilibrium.
D)all of the above
E)none of the above

Question 54

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction. The particle with both forces acting

A)is brought to a rapid halt.
B)decelerates gradually to a halt.
C)continues at the speed it had when it encountered the second force.
D)theoretically tends to accelerate toward the speed of light.
E)none of the above

Question 55

A rock is thrown vertically into the air. At the top of its path, its acceleration is

A)zero.
B)10 m/s².
C)between 0 and 10 m/s².
D)greater than 10 m/s².

Question 56

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

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

Question 57

A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration when taking off?

A)0.25 m/s²
B)1 m/s²
C)2 m/s²
D)4 m/s²
E)none of the above

Question 58

A force of 1 N accelerates 1-kg box at the rate of 1 m/s². The acceleration of a 2-kg box by a net force of 2 N is

A)half as much.
B)twice as much.
C)the same.
D)none of the above

Question 59

A rock is thrown vertically into the air. At the top of its path the net force on it is

A)less than mg.
B)mg.
C)more than mg.

Question 60

Nellie pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration?

A)0.3 m/s²
B)3.0 m/s²
C)10 m/s²
D)30 m/s²
E)300 m/s²

Question 61

A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about

A)1/2 N.
B)1 N.
C)5 N.
D)7.5 N.
E)10 N.

Question 62

Two factors that greatly affect air resistance on falling objects are frontal area and

A)mass.
B)weight.
C)speed.

Question 63

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was

A)1.2 m/s.
B)15 m/s.
C)30 m/s.
D)45 m/s.
E)none of the above

Question 64

Recall Galileo's Leaning Tower experiment. With negligible air resistance, a heavy and a light object fall

A)with equal accelerations.
B)with the same increases in speed.
C)to the ground in equal times.
D)all of the above

Question 65

A feather and a coin will have equal accelerations when falling in a vacuum because

A)their velocities are the same.
B)the force of gravity is the same for each in a vacuum.
C)the force of gravity does not act in a vacuum.
D)the ratio of both the feather's and coin's weight to mass is the same.
E)none of the above

Question 66

An astronaut on another planet drops a 1-kg rock from rest. The astronaut notices that the rock falls 2 meters straight down in one second. On this planet, how much does the rock weigh?

A)1 N
B)4 N
C)5 N
D)10 N

Question 67

A 10-kg brick and a 1-kg apple are dropped in a vacuum. The force of gravity on the brick is

A)the same as the force on the apple.
B)10 times more than the force on the apple.
C)one-tenth as much as on the apple.
D)zero.

Question 68

A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time?

A)100 m
B)200 m
C)300 m
D)400 m
E)none of the above

Question 69

An object released from rest on another planet requires one second to fall a distance of 6 meters. What is the acceleration due to gravity on this planet?

A)3 m/s²
B)6 m/s²
C)12 m/s²
D)15 m/s²
E)none of the above

Question 70

An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, the rock has a weight of

A)1 N.
B)2 N.
C)3 N.
D)4 N.
E)5 N.

Question 71

Scotty Skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of about

A)0.2 g.
B)0.3 g.
C)0.4 g.
D)0.5 g.
E)greater than 0.5 g.

Question 72

A bowling ball and a baseball accelerate equally when falling in a vacuum because

A)their velocities are the same.
B)the ratio of their weights to mass is the same.
C)the force of gravity is the same for each in a vacuum.
D)the force of gravity does not act in a vacuum.
E)none of the above

Question 73

A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about

A)5 N.
B)10 N.
C)25 N.
D)50 N.
E)none of the above

Question 74

A 10-kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block is

A)1 m/s².
B)2 m/s².
C)5 m/s².
D)10 m/s².
E)none of the above

Question 75

The human body can withstand an acceleration of 10 g under certain conditions. What net force would produce this acceleration for a 50-kg person?

A)500 N
B)2500 N
C)5000 N
D)25,000 N
E)none of the above

Question 76

What horizontally-applied force will accelerate a 400-kg crate at 1 m/s² across a factory floor against a friction force half its weight?

A)600 N
B)1600 N
C)2000 N
D)2400 N
E)none of the above

Question 77

If you are driving at 20 m/s and slam on your brakes and skid at 0.5g to a full stop, the skidding time is about

A) 3 s.
B) 4 s.
C) 5 s.
D) 6 s.
E)greater than 6 s.

Question 78

A single brick falls with acceleration g. The reason a double brick falls with the same acceleration is

A)that in free fall all accelerations are g.
B)its ratio of force to mass is the same.
C)an experimental fact tested many times.
D)none of the above

Question 79

A car traveling at 22 m/s comes to an abrupt halt in 0.1 second when it hits a tree. What is the deceleration of the car?

A)110 m/s²
B)220 m/s²
C)800 m/s²
D)880 m/s²
E)need more information

Question 80

The brakes of a speeding truck are slammed on and it skids to a stop. If the truck were heavily loaded so that it had twice the total mass, the skidding distance would be

A)half as far.
B)1.5 times as far.
C)twice as far.
D)4 times as far.
E)the same.