Deck 3: Force and Motion

Question 1

If an object of mass 6 kg has an acceleration of 9 m/s²,what is the unbalanced force acting on it?

A) 54 N
B) 0.67 N
C) 1.5 N
D) 15 N
E) cannot be determined

Answer 1

A

Question 2

The SI base units making up the newton are

A) kg m/s.
B) g m/s².
C) kg m/s².
D) kg²/s.

Answer 2

C

Question 3

An automobile travels due north with a speed of 68 km/h and an acceleration of 1.5 m/s².All forces considered,the unbalanced force acting on the auto is

A) zero.
B) southward.
C) northward.
D) downward.
E) upward.

Answer 3

C

Question 4

Mass and weight on Earth's surface

A) are the same thing.
B) are defined solely by inertia.
C) are explained by Newton's third law.
D) differ in magnitude by a constant.
E) are explained by Kepler's second law.

Question 5

A mass is accelerated when ______________ acts upon the mass.

A) a balanced force
B) any force
C) no force
D) an unbalanced force
E) none of these

Question 6

The essentials of the first law of motion were initially developed by

A) Aristotle.
B) Galileo.
C) Newton.
D) an unknown scientist.

Question 7

An automobile travels due north with a constant speed of 81 km/h.All forces considered,the unbalanced force acting on the auto is

A) zero.
B) southward.
C) northward.
D) downward.
E) upward.

Question 8

If a person weighs 108 lb on Earth,that person's weight on the Moon would be

A) 648 lb.
B) 54 lb.
C) 18 lb.
D) 108 lb.
E) 54 lb.

Question 9

The acceleration produced by an unbalanced force acting on an object is

A) inversely proportional to the mass of the object.
B) directly proportional to the magnitude of the force.
C) in the direction of the force.
D) all of these.

Question 10

A spacecraft in space keeps going at the same velocity,even without firing its rockets,in accordance with the _______________ law of motion.

A) fourth
B) first
C) second
D) third

Question 11

When you push on a stationary object on a horizontal surface and it doesn't move,what kind of force is most likely opposing your efforts?

A) Static friction force
B) Sliding friction force
C) Lubricant friction force
D) Gravitational force
E) Normal Force

Question 12

Two equal and opposite forces of 6.0 N act on an object.The unbalanced force on the object

A) is 6.0 N.
B) is 0 N.
C) is 8 N.
D) is 12 N.
E) cannot be determined from given information.

Question 13

When a net force on a moving object increases,the object will

A) maintain the same velocity.
B) always show an increase in speed.
C) exhibit a change in speed and/or direction.
D) maintain a constant acceleration.

Question 14

It is generally easier to push an object once it is moving than when you are getting it started.This is because

A) sliding friction is zero.
B) sliding friction is less than static friction.
C) static friction is less than sliding friction.
D) static friction is zero.

Question 15

On which planet (other than Earth)have air bags been deployed?

A) Venus
B) Mars
C) Mercury
D) Saturn

Question 16

Mass is a measure of

A) inertia.
B) force.
C) grams.
D) weight.
E) kilograms.

Question 17

An automobile air bag

A) increases the contact time in stopping a person.
B) reduces the impact force in a collision.
C) increases the surface area of the impact force.
D) does all of the above.

Question 18

A constant net force acting on an object that is free to move will produce a constant

A) speed.
B) velocity.
C) displacement.
D) acceleration.
E) distance.

Question 19

An automobile travels due north with a speed of 77 km/h that is decreasing.All forces considered,the unbalanced force acting on the auto is

A) zero.
B) southward.
C) northward.
D) downward.
E) upward.

Question 20

The natural tendency of an object to remain at rest or in motion with a constant velocity is called

A) an external force.
B) an unbalanced force.
C) inertia.
D) none of these.

Question 21

If an unbalanced force of 8 N force acts on a 7-kg object,what is its acceleration?

A) 56 m/s²
B) 1.1 m/s²
C) 0.88 m/s²
D) 15 m/s²
E) cannot be determined

Question 22

Which of the following would be different for a person on the Moon rather than on Earth?

A) Weight
B) Height
C) Volume
D) Mass

Question 23

If an object on Earth weighs 100 N,what is its weight in pounds?

A) 22
B) 100
C) 10
D) 220
E) 450

Question 24

Newton's third law of motion states that the force pair acting on different objects consists of two forces that

A) are under the influence of gravity.
B) are equal and in the same direction.
C) always produce an acceleration.
D) are equal and in opposite directions.

Question 25

______________ principle explains why objects float or sink in a fluid.

A) Newton's
B) Pascal's
C) Bernoulli's
D) Archimedes'

Question 26

Newton's law of universal gravitation is believed to be applicable

A) to the Milky Way only.
B) on Earth and the Moon only.
C) throughout the universe.
D) to the solar system only.
E) on Earth only.

Question 27

"For every action there is an equal and opposite reaction" is a statement of Newton's

A) law of universal gravitation.
B) first law.
C) second law.
D) third law.

Question 28

The relationship between mass and weight is given by the equation

A) m = wg.
B) w = m/g.
C) g = mw.
D) w = mg.

Question 29

In the equation A = B/C,the B and C are said to be _______________ proportional.

A) directly
B) inversely
C) not
D) exactly

Question 30

If the lever arm of a 9-N force is 6 m,what is the torque acting on the object due to this force?

A) 54 Nm
B) 1.5 Nm
C) 0.67 Nm
D) 15 Nm
E) cannot be determined

Question 31

The buoyant force of an object is equal to the ______________ of the ______________ it displaces.

A) mass; fluid
B) weight; fluid
C) mass; solid
D) weight; solid

Question 32

If an object of mass 8 kg has a velocity of 7 m/s,what is its linear momentum?

A) 56 kg-m/s
B) 1.1 kg-m/s
C) 0.88 kg-m/s
D) 15 kg-m/s
E) cannot be determined

Question 33

In the equation A = B/C,the A and C are said to be _______________ proportional.

A) directly
B) inversely
C) not
D) exactly

Question 34

According to Newton's second law,the force required to accelerate an object is equal to

A) its acceleration divided by its mass.
B) its mass times the acceleration.
C) its mass divided by the velocity.
D) its weight times the velocity.

Question 35

An object will ______________ in a fluid if its average density is ______________ the density of the fluid.

A) float; greater than
B) float; less than
C) sink; less than
D) sink; equal to

Question 36

Which of the following would be the same for a person on the Moon rather than on Earth?

A) Maximum jumping height
B) Weight
C) The amount of time for an object to fall 2 meters from rest
D) Mass
E) Gravitational acceleration

Question 37

An object will ______________ in a fluid if its average density is ______________ the density of the fluid.

A) sink; greater than
B) float; equal to
C) sink; less than
D) float; twice

Question 38

The gravitational pull of Earth acting on an object is zero when the object

A) has zero acceleration.
B) is in free fall.
C) is midway between Earth and the Moon.
D) is in orbit around Earth.
E) none of these

Question 39

In the equation A = B/C,the A and B are said to be _______________ proportional.

A) directly
B) inversely
C) not
D) exactly

Question 40

"Weightlessness" occurs when an object

A) has zero acceleration.
B) is in free fall.
C) is midway between Earth and the Moon.
D) loses weight.

Question 41

What must be exerted on an object to change the angular momentum?

A) Linear momentum
B) Torque
C) A force parallel to the motion
D) Inertia

Question 42

Two of your classmates,each 82 kg,are separated by 4 meters.The gravitational force of attraction between them in nano-newtons is

A) 1.4 nN
B) 0.3 nN
C) 0.0 nN
D) 41.2 nN
E) 28.0 nN

Question 43

In an equation,the symbol m generally stands for

A) inertia.
B) torque.
C) momentum.
D) mass.
E) meters.

Question 44

Linear momentum

A) has the units of mass times acceleration.
B) has magnitude and direction.
C) is a scalar quantity.
D) none of these

Question 45

To cause an object to move in a circle,a ______________ force is necessary.

A) balanced
B) functional
C) centripetal
D) centrifugal

Question 46

The variable r that appears in the equation F = Gm₁m₂/r² is

A) the straight-line distance between the centers of the two masses.
B) the rate at which both objects are moving.
C) the radius of the first mass.
D) the radius of the second mass.

Question 47

The angular momentum of a 100.0 kg object moving around a 75.0 m circle at a constant speed of 3.90 m/s is

A) 0.0 N
B) 29250 N
C) 761 N
D) 390 N

Question 48

The constant G that appears in the equation F = Gm₁m₂/r² is

A) smaller on the Moon than on Earth.
B) the force of gravity.
C) equal to 9.8 m/s².
D) the acceleration due to gravity.
E) equal to 6.67 x 10^-11 Nm²/kg².

Question 49

The speed of a comet in its orbit around the Sun is ______________ when its distance from the Sun is least (perihelion).

A) zero
B) reversed
C) greatest
D) least

Question 50

The acceleration of an object acted on by a net force perpendicular to the direction of the object's original motion

A) causes a change in direction.
B) is described by Newton's laws.
C) causes a change in velocity.
D) all of these

Question 51

The quantity mvr is an object's

A) inertia.
B) torque.
C) linear momentum.
D) angular momentum.

Question 52

The linear momentum of a 100.0 kg object moving around a 30.0 m circle at a constant speed of 2.20 m/s is

A) 0.0 N
B) 220 N
C) 242 N
D) 6600 N

Question 53

A change in motion requires a(n)______________.

Question 54

The constant G that appears in the equation F = Gm₁m₂/r² is

A) smaller on the Moon than on Earth.
B) the force of gravity.
C) equal to g.
D) the acceleration due to gravity.
E) a universal constant.

Question 55

The linear momentum of an object can be determined by taking the product of the mass and the

A) acceleration of the object.
B) velocity of the object.
C) distance the object moves.
D) displacement of the object.

Question 56

The total linear momentum of an isolated system of masses remains the same if there are no external ______________ acting on the system.

A) forces
B) torques
C) unbalanced forces
D) unbalanced torques

Question 57

The speed of a comet in its orbit around the Sun is ______________ when its distance from the Sun is greatest (aphelion).

A) zero
B) reversed
C) greatest
D) least

Question 58

The variables m₁ and m₂ that appear in the equation F = Gm₁m₂/r² are

A) the straight-line distance between the centers of each object.
B) the rate at which each object is moving.
C) the mass of each object.
D) the diameter of each object.

Question 59

The force required to move a 90.0 kg object in a 85.0 m circle at a constant speed of 8.10 m/s is

A) 0.0 N
B) 69.5 N
C) 0.77 N
D) 8.58 N

Question 60

The angular momentum of a body is constant if the

A) net torque is zero.
B) net force is constant.
C) net torque is constant.
D) net force is zero.

Question 61

Newton's third law of motion states that whenever one object exerts a force upon a second object,the second object exerts a(n)______________ and ______________ force upon the first object.

Question 62

An apple weighs approximately one ______________.

Question 63

The acceleration of an object with a zero net force acting on it is ______________.

Question 64

Force is a(n)______________ quantity.

Question 65

The natural tendency of an object to remain at rest or in uniform straight-line motion is called ______________.

Question 66

A quantity that is capable of producing motion or a change in motion is called a(n)______________.

Question 67

In the SI,weight is expressed in units of ______________.

Question 68

An acceleration is evidence of ______________.

Question 69

In keeping with Newton's second law of motion,if the force acting on a moving object is doubled,then its ______________ is doubled.

Question 70

Newton's third law force pair acts on ______________ objects.

Question 71

Forces always occur in ______________.

Question 72

Jet propulsion can be explained in terms of Newton's third law and the ______________.

Question 73

An astronaut on the Moon has the same mass as when on Earth,but has a different ______________.

Question 74

a = F/m is a statement of ______________.

Question 75

An indication of an object's inertia is given by its ______________.

Question 76

In Newton's law of universal gravitation,F = Gm₁m₂/r² for uniform objects,the quantity r is______________.

Question 77

A(n)______________ force is necessary for uniform circular motion.

Question 78

To initiate motion,a(n)______________ force is necessary.

Question 79

A student stands on a chair.The forces acting on her or him are supplied by gravity acting downward and by the ______________ acting upward.

Question 80

For Newton's third law,the action and reaction forces are equal in ______________ and opposite in direction.