Deck 3: Optics and Wave Effects

Question 1

An automobile travels due north with a constant speed of 76 km/h. All forces considered, the unbalanced force acting on the auto is

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

Answer 1

A

Question 2

If an object of mass 8 kg has an acceleration of 5 m/s², what is the unbalanced force acting on it?

A) 40 N
B) 1.6 N
C) 0.63 N
D) 13 N
E) cannot be determined

Answer 2

A

Question 3

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.

Answer 3

C

Question 4

An automobile travels due north with a speed of 93 km/h and an acceleration of 1.6 m/s². All forces considered, the unbalanced force acting on the auto is

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

Question 5

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

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

Question 6

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

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

Question 7

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 8

Mass is a measure of

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

Question 9

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 10

The SI base units making up the newton are

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

Question 11

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 12

Two equal and opposite forces of 3.0 N act on an object. The unbalanced force on the object

A) is 3.0 N.
B) is 0 N.
C) is 5 N.
D) is 6 N.
E) cannot be determined from given information.

Question 13

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 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

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 16

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 17

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 18

If a person weighs 186 lb on Earth, that person's weight on the Moon would be

A) 1116 lb.
B) 93 lb.
C) 31 lb.
D) 186 lb.
E) 93 lb.

Question 19

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 20

An automobile travels due north with a speed of 92 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 21

If the lever arm of a 5-N force is 7 m, what is the torque acting on the object due to this force?

A) 35 Nm
B) 0.71 Nm
C) 1.4 Nm
D) 12 Nm
E) cannot be determined

Question 22

If an object of mass 9 kg has a velocity of 7 m/s, what is its linear momentum?

A) 63 kg-m/s
B) 1.3 kg-m/s
C) 0.78 kg-m/s
D) 16 kg-m/s
E) cannot be determined

Question 23

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 24

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 25

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 26

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 27

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 28

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

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

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

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 31

If an unbalanced force of 5 N force acts on a 8-kg object, what is its acceleration?

A) 40 m/s²
B) 0.63 m/s²
C) 1.6 m/s²
D) 13 m/s²
E) cannot be determined

Question 32

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

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

Question 33

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

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

Question 34

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 35

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 36

"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 37

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 38

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 39

"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 40

If an object on Earth weighs 300 N, what is its weight in pounds?

A) 67
B) 300
C) 31
D) 660
E) 1300

Question 41

A change in motion requires a(n) ____________.

Question 42

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 43

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 44

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 45

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 46

The quantity mvr is an object's

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

Question 47

The linear momentum of a 40.0 kg object moving around a 90.0 m circle at a constant speed of 7.60 m/s is

A) 0.0 N
B) 304 N
C) 1155 N
D) 27360 N

Question 48

Two of your classmates, each 82 kg, are separated by 2 meters. The gravitational force of attraction between them in nano-newtons is

A) 2.7 nN
B) 1.4 nN
C) 0.0 nN
D) 164.7 nN
E) 112.1 nN

Question 49

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 50

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

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

Question 51

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 52

The force required to move a 50.0 kg object in a 55.0 m circle at a constant speed of 2.60 m/s is

A) 0.0 N
B) 6.1 N
C) 0.12 N
D) 2.36 N

Question 53

In an equation, the symbol m generally stands for

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

Question 54

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 55

The angular momentum of a 30.0 kg object moving around a 50.0 m circle at a constant speed of 2.70 m/s is

A) 0.0 N
B) 4050 N
C) 109 N
D) 81 N

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 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 58

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 59

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 60

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 61

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

Question 62

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

Question 63

Forces always occur in ____________.

Question 64

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

Question 65

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

Question 66

An apple weighs approximately one ______________.

Question 67

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

Question 68

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

Question 69

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

Question 70

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

Question 71

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 72

Force is a(n) ______________ quantity.

Question 73

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

Question 74

a = F/m is a statement of ______________.

Question 75

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

Question 76

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

Question 77

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

Question 78

An acceleration is evidence of ______________.

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.