Physics Chapter 1 Introduction and Mathematical Concepts

10 Is it possible for an object to have an acceleration when the speed of the object is constant? A)Yes B) No

A

24 Sound wave is a longitudinal wave. A)True B)False

A

Complete the following statement: Today, the standard unit of time is defined in terms of A) the electromagnetic waves emitted by cesium atoms. B) the motion of the moon around the earth. C) the motion of a precision pendulum. D) the average solar day. E) the speed of light.

A

Is a net force being applied to an object when the object is moving downward with a constant acceleration of 9.80 m/s2. A. Yes B. No C. There is not enough information to decide.

A

SI unit of acceleration is A. m/s2 B. m/s C. m.s D. m/s3

A

Two vectors A and B are added together to form a vector C . The relationship between the magnitudes of the vectors is given by: A2 + B2 = C2. Which statement concerning these vectors is true? a) A and B must be at right angles to each other. b)A and B could have any orientation relative to each other. c) A and B must have equal lengths. d) A and B must be parallel. e) A and B could be antiparallel.

A

A ball hung from a vertical spring oscillates in simple harmonic motion with an angular frequency of 2.6 rad/s and an amplitude of 0.075 m. What is the maximum acceleration of the ball? A) 0.51 m/s2 B) 0.20 m/s2 C) 35 m/s2 D) 0.13 m/s2 E) 2.6 m/s2

A) 0.51 m/s2

During a one-hour trip, a small boat travels 80.0 km north and then travels 60.0 km east. What is the boat's displacement for the one-hour trip? A) 100 km B) 10,000 km C) 280 km D) 20 km E) 140 km

A) 100 km

14 A projectile is launched with a momentum of 200 kg·m/s and 1000 J of kinetic energy. What is the mass of the projectile? A) 20 kg B) 50 kg C) 5 kg D) 40 kg E) 10 kg

A) 20 kg

Jennifer is walking at 1.22 m/s. If Jennifer weighs 552 N, what is the magnitude of her momentum? A) 951 kg·m/s B) 68.7 kg·m/s C) 137 kg·m/s D) 672 kg·m/s E) 97.0 kg·m/s

B) 68.7 kg·m/s

A wrench is used to tighten a nut as shown in the figure. A 12-N force is applied 7.0 cm from the axis of rotation. What is the magnitude of the torque due to the applied force? A. 0.58 N.m B. 0.84 N.m C. 1.71 N.m D. 14 N.m E. 58 N.m

B. 0.84 N.m

Complete the following statement: When a net torque is applied to a rigid object, it always produces a A. constant acceleration. B. rotational equilibrium. C. constant angular velocity. D. change in angular velocity.

D

Two cars are traveling at the same constant speed v. Car A is moving along a straight section of the road, while B is rounding a circular turn. Which statement is true about the acceleration of the cars? A. Car A is accelerating, but car B is not accelerating. B. Car A is accelerating, but car B is not accelerating. C. The acceleration of both cars is zero, since they are traveling at a constant speed. D. Car A is not accelerating, but car B is accelerating.

D

A car has a mass of 1600 kg. It is stuck in the snow and is being pulled out by a cable that applies a force of 7560 N due north. The resistance of the snow and mud also applies a force to the car, which has a magnitude of 7340 N and points due south. What is the acceleration of the car? A. 4.7 m/s2 north B. 4.6 m/s2 south C. 9.3 m/s2 south D. 0.14 m/s2 north E. There is not enough information to determine the car's acceleration.

D. 0.14 m/s2 north

______________ deals with the effect that forces have on motion.

Dynamics

Complete the following statement: A body is in translational equilibrium A) if it is moving with either constant velocity or constant acceleration. B)only if it is moving with constant velocity. C)only if it is at rest. D)only if it is moving with constant acceleration. E)if it is either at rest or moving with constant velocity.

E

8 A cheetah has an acceleration that has x and y components of ax = 5.3 m/s2 and ay = 3.8 m/s2. The cheetah's mass is 61 kg. Find the net force acting on the cheetah. A) 2.3 x 102 N, directed 54° above the x axis B) 4.0 x 102 N, directed 54° above the x axis C) 5.6 x 102 N, directed 36° above the x axis D) 3.2 x 102 N, directed 36° above the x axis E) 4.0 x 102 N, directed 36° above the x axis

E) 4.0 x 102 N, directed 36° above the x axis

One in which the total kinetic energy of the system after the collision is equal to the total kinetic energy before the collision.

Elastic collision

Forces exerted on objects by agents external to the system.

External forces

An object is in equilibrium when it has zero _____________

acceleration

Changing angular velocity means that an angular _______________ is occurring.

acceleration

The notion of _____________ emerges when a change in velocity is combined with the time during which the change occurs.

acceleration

Under the influence of gravity ___________, an object near the surface of the Earth will accelerate downwards at 9.80 m/s2.

alone

In simple harmonic motion, an object oscillates with a constant _____________.

amplitude

For small angles, the torque that restores the pendulum to its vertical equilibrium position is proportional to the _____________________.

angular displacement

The angle through which the object rotates is called the______________________

angular displacement

The ___________ weight of an object is the reading of the scale.

apparent

What causes an object to have an angular acceleration?

TORQUE

angular displacement over elapsed time

average angular velocity

Impulse is a vector quantity and has the same direction as the _____________

average force

In the simplest kind of rotation, points on a rigid object move on circular paths around an ________________.

axis of rotation

In an inelastic collision the total kinetic energy of the system after the collision is equal to the total kinetic energy before the collision. (a)True (b)False

b

Is the acceleration of a projectile equal to zero when it reaches the top of its trajectory? (a)Yes (b)No (c)There is not enough information to decide.

b

The units for length, mass, and time (as well as a few others), are regarded as _______________.

base SI units

At contact points the molecules of the different bodies are close enough together to exert strong attractive intermolecular forces on one another, leading to what are known as "_____________."

cold welds

A force is ______________ when the work it does on a moving object is independent of the path between the object's initial and final positions

conservative

The total mechanical energy (E = KE + PE) of an object remains _____________ as the object moves, provided that the net work done by external nonconservative forces is zero.

constant

The total linear momentum of an isolated system is _________ (conserved). An isolated system is one for which the sum of the average external forces acting on the system is ________.

constant, zero

The torque is positive when the force tends to produce a _______________ rotation about the axis.

counterclockwise

__________: The smallest degree of damping that completely eliminates the oscillations is termed "critical damping" and the motion is said to be critically damped.

critically damped

One kilogram is defined to be the mass of a standard _____________ of platinum-iridium alloy.

cylinder

In uniform circular motion, the speed, or the magnitude of the velocity vector, is constant, but the _______ of the velocity vector is not constant.

direction

HOOKE'S LAW FOR STRESS AND STRAIN Stress is ________ proportional to strain. Strain is a unitless quantity. SI Unit of Stress: N/m2

directly

Action-at-a-___________ forces do not require contact and include gravity and electrical forces.

distance

A wave is a traveling _____________

disturbance

When a force is applied to an oscillating system at all times, the result is ___________________ Here, the driving force has the same frequency as the spring system and always points in the direction of the object's velocity.

driven harmonic motion

An object is in simple harmonic motion. The rate at which the object oscillates may be described using the period T, the frequency f, and the angular frequency . If the angular frequency decreases, what is the effect on the period and the frequency? a) The frequency would decrease, but the period would remain the same. b) The period would increase, but the frequency would remain the same. c) Both the period and the frequency would decrease. d) Both the period and the frequency would increase. e) The period would increase, and the frequency would decrease

e

A ball of mass m is attached to the end of a spring that has a spring constant k. When the ball is displaced from its equilibrium position and released, it moves in simple harmonic motion. Consider the relationship between the angular frequency, the mass, and the spring constant given in the text. Which one of the following statements concerning that relationship is true? a) Increasing the spring constant causes the angular frequency to increase. b) Increasing the mass of the ball causes the angular frequency to increase. c) Increasing the initial displacement before releasing the ball causes the angular frequency to increase. d) Increasing the period of the ball's motion causes the angular frequency to increase.

e) at 0 s, 4 s, and 8 s

The _________ potential energy is the energy that a spring has by virtue of being stretched or compressed

elastic

If the net work on an object by nonconservative forces is zero, then its __________ does not change:

energy

A _________ is a push or a pull.

force

. This parallel force component is called the frictional force, or simply_________.

friction

When an object has a symmetrical shape and its weight is distributed uniformly, the center of gravity lies at its ________________ center

geometrical

The weight of an object on or above the earth is the __________________ that the earth exerts on the object. The weight always acts downwards, toward the center of the earth. On or above another astronomical body, the weight is the gravitational force exerted on the object by that body.

gravitational force

Static friction opposes the _________ relative motion between two objects. Kinetic friction opposes the relative ________ motion that actually does occur.

impending, sliding

The________of a force is the product of the average force and the time interval during which the force acts

impulse

The mass of an object is a quantitative measure of _________.

inertia

The _______________ indicates how fast the car moves and the direction of motion at each instant of time.

instantaneous velocity

SI Unit of Elastic Potential Energy: ________

joule

SI Unit of Rotational Work: __________

joule

unit of mass

kilogram

Physics predicts how ____________ will behave in one situation based on the results of experimental data obtained in another situation

nature

The work done by the kinetic frictional force is always ___________. Thus, it is impossible for the work it does on an object that moves around a closed path to be zero.

negative

The __________ is the vector sum of all of the forces acting on an object.

net force

Thus, in uniform circular motion there must be a _________ to produce the centripetal acceleration. The centripetal force is the name given to the net force required to keep an object moving on a circular path. The direction of the centripetal force always points toward the center of the circle and continually changes direction as the object moves.

net force

The speed at which the wave moves to the right depends on how quickly one particle of the string is accelerated upward in response to the______________________.

net pulling force

A force is conservative when it does _____ work on an object moving around a closed path, starting and finishing at the same point.

no

At each moment during its flight, a projectile has a velocity and an acceleration . The components of these variables are: vx = x component of the velocity vy = y component of the velocity ax = x component of the acceleration ay = y component of the acceleration. Which of these components remain constant throughout the motion? Assume that air resistance is absent. (a) vx , ax and ay are constant. (b) Only ax and ay are constant. (c) vy , ax and ay are constant. (d) Only vx and ay are constant. (e) None of these variables is constant

a

All accelerating reference frames are __________

noninertial

The ______________ is one component of the force that a surface exerts on an object with which it is in contact - namely, the component that is perpendicular to the surface.

normal force

When the damping exceeds critical value, the motion is said to be ______________.

overdamped

car takes longest time to return to its equilibrium position

overdamped

Physics has developed out of the efforts of men and women to explain our _________________________

physical environment

The brain interprets the frequency in terms of the subjective quality called __________.

pitch

By convention, the angular displacement is ___________ if it is counterclockwise and ____________ if it is clockwise.

positive, negative

Average _________ is the rate at which work is done, and it is obtained by dividing the work by the time required to perform the work

power

Loudness is an attribute of a sound that depends primarily on the ________________________ of the wave.

pressure amplitude

A sound with a single frequency is called a ______________

pure tone

In _________________________ motion, all points on an object travel on parallel paths.

pure translational

Physics experiments involve the measurement of a variety of _______________.

quantities

SI Unit of Angular Displacement: ________

radian

SI Unit of Angular Velocity

radian per second

SI Unit of Angular acceleration: ____________________

radian per second squared

The most general motion is a combination of translation and ______________.

rotation

A __________ quantity is one that can be described by a single number: temperature, speed, mass

scalar

unit of time

second

A simple pendulum swinging back and forth about the pivot P. If the angle θ is small, the swinging is approximately ___________________

simple harmonic motion

The cylinder with the ____________ moment of inertia will have a greater final translational speed

smaller

Uniform circular motion is the motion of an object traveling at a constant __________ on a circular path.

speed

On an unbanked curve, the _________ frictional force provides the centripetal force.

static

When the two surfaces are not sliding across one another the friction is called ________ friction. Applying a small force to the block produces no movement, because the static frictional force exactly balances the applied force. The block just begins to move when the applied force is slightly greater than the maximum static frictional force .

static

In general the quantity F/A is called the ____________

stress

where the Greek letter sigma denotes the vector ______

sum

Cables and ropes transmit forces through ___________

tension

The amount of _________ depends on where and in what direction the force is applied, as well as the location of the axis of rotation

torque

Individual air molecules are not carried along with the wave

true

The concept of potential energy is not defined for a nonconservative force.

true

acceleration can be negative

true

When the damping is less than critical level, the motion is said to be _______________

underdamped

The first step in ensuring accuracy and reproducibility is defining the ______________ in which the measurements are made.

units

An inertial reference frame is one in which Newton's Law of Inertia is _________

valid

A ________ quantity deals inherently with both magnitude and direction: velocity, force, displacement

vector

In an isolated system, the total linear momentum does not change, therefore the ___________ of the center of mass does not change

velocity

__________ carries energy from place to place

wave

The distance between adjacent condensations is equal to the ___________ of the sound wav

wavelength

The center of gravity of a rigid body is the point at which its weight can be considered to act when the torque due to the ___________ is being calculated.

weight

THE WORK-ENERGY THEOREM When a net external force does work on an object, the kinetic energy of the object changes by the amount of ______ done on it:

work

DEFINITION OF GRAVITATIONAL POTENTIAL ENERGY The gravitational potential energy PE is the energy that an object of mass m has by virtue of its position relative to the surface of the earth. That position is measured by the height h of the object relative to an arbitrary ________ level

zero

PRINCIPLE OF CONSERVATION OF ANGULAR MOMENTUM The angular momentum of a system remains constant (is conserved) if the net external torque acting on the system is ________.

zero

_______________ deals with the concepts that are needed to describe motion.

Kinematics

________ is a measure of the amount of "stuff" contained in an object

Mass

Together, kinematics and dynamics form the branch of physics known as ____________.

Mechanics

____________ consist of cycles or patterns that are produced over and over again by the source.

Periodic waves

_______________ is the condition in which a time-dependent applied force can transmit large amounts of energy to an oscillating object, leading to a large amplitude motion.

Resonance

________________ occurs when the frequency of the applied force matches a natural frequency at which the object will oscillate.

Resonance

_______________ waves are partially transverse and partially longitudinal

Water

Sound travels through gases, liquids, and solids at considerably _________________.

different speeds

In Physics, the term _______________ is used to refer to the physical nature of a quantity and the type of unit used to specify it.

dimension

At a certain point along the path in projectile motion, the projectile has a velocity V whose scalar components are vx = +30 m/s and vy = +40 m/s. As the projectile moves along the path, what would be its minimum speed? (a)0 m/s (b)30 m/s (c)40 m/s (d)50 m/s (e)60 m/s

(b)30 m/s

Suppose that a NASCAR race car is moving to the right with a constant velocity of +82 m/s. Twelve seconds later, the car is halfway around the track and traveling in the opposite direction with the same speed. What is the average acceleration of the car? (a) + 82 m/s2 (b) +14 m/s2 (c) -14 m/s2 (d) - 82 m/s2 (e) +92 m/s2

(c) -14 m/s2

A jogger runs along a straight and level road for a distance of 8.0 km and then runs back to her starting point. The time for this round-trip is 2.0 h. Which one of the following statements is true? (a) Her average speed is 8.0 km/h, but there is not enough information to determine her average velocity. (b) Her average speed is 8.0 km/h, and her average velocity is 8.0 km/h. (c) Her average speed is 8.0 km/h, and her average velocity is 0 km/h.

(c) Her average speed is 8.0 km/h, and her average velocity is 0 km/h.

What is the difference between distance and displacement? A)There is no difference between the two concepts; they may be used interchangeably. B)Displacement is a vector, while distance is not a vector. C)Distance is a vector, while displacement is not a vector.

B

On an amusement park ride, passengers are seated in a horizontal circle of radius 7.5 m. The seats begin from rest and are uniformly accelerated for 21 seconds to a maximum rotational speed of 1.4 rad/s. What is the tangential acceleration of the passengers during the first 21 s of the ride? A) 0.067 m/s2 B) 0.50 m/s2 C) 1.4 m/s2 D) 7.5 m/s2 E) 11 m/s2

B) 0.50 m/s2

An 80-kg man balances the boy on a teeter-totter as shown. Note: Ignore the weight of the board. What is the approximate mass of the boy? A) 10 kg B) 20 kg C) 40 kg D) 45 kg E) 50 kg

B) 20 kg

A small fan has blades that have a radius of 0.0600 m. When the fan is turned on, the tips of the blades have a tangential acceleration of 14.0 m/s2 as the fan comes up to speed. What is the angular acceleration αof the blades? A) 105 rad/s2 B) 233 rad/s2 C) 155 rad/s2 D) 300 rad/s2 E) 50.5 rad/s2

B) 233 rad/s2

Complete the following statement: The angular measure 1.0 radian is equal to A) 0.0175°. B) 57.3°. C) 1.57°. D) 3.14°. E) 6.28°.

B) 57.3°

__________________ is the distance traveled divided by the time required to cover the distance.

Average speed

___________________ is the displacement divided by the elapsed time.

Average velocity

A baseball of mass m, initially at rest, is struck by a bat so that it acquires a speed v. If t represents the duration of the collision between the bat and the ball, which one of the following expressions determines the magnitude of the average force exerted on the ball? A) mvt B) mv/t C) (1/2)mv2t D) mt2/(2v) E) (1/2)mv2

B

In a transverse wave the disturbance always occurs parallel to the line of travel of the wave, whereas in a longitudinal wave the disturbance always occurs perpendicular to the direction in which the wave travels. A) True B) False

B

A father and his seven-year-old daughter are facing each other on ice skates. With their hands, they push off against one another. Compare the magnitudes of the pushing forces that they experience. A. The father experiences a larger pushing force. B. The daughter experiences a larger pushing force. C. Both father and daughter experience pushing forces of equal magnitude.

C

A wheel with a 0.10-m radius is rotating at 35 rev/s. It then slows uniformly to 15 rev/s over a 3.0-s interval. What is the angular acceleration of a point on the wheel? A)-2.0 rev/s2 B)0.67 rev/s2 C)-6.7 rev/s2 D)42 rev/s2 E)-17 rev/s2

C)-6.7 rev/s2

________ forces arise from physical contact .

Contact

One in which the total kinetic energy of the system after the collision is not equal to the total kinetic energy before the collision; if the objects stick together after colliding, the collision is said to be completely __________.

Inelastic collision

_________ is the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line.

Inertia

Forces that objects within the system exert on each other.

Internal forces

The SI unit of force is the

Newton

When a net external force acts on an object of mass m, the acceleration that results is directly proportional to the net force and has a magnitude that is inversely proportional to the mass. The direction of the acceleration is the same as the direction of the net force.

Newton's Second Law

Whenever one body exerts a force on a second body, the second body exerts an oppositely directed force of equal magnitude on the first body.

Newton's Third Law of Motion

An object continues in a state of rest or in a state of motion at a constant speed along a straight line, unless compelled to change that state by a net force.

Newtons First Law

The direction of the centripetal acceleration is towards the __________ of the circle; in the same direction as the change in velocity.

center

The _____________ is a point that represents the average location for the total mass of a system.

center of mass

We use the electromagnetic waves emitted by ________ -133 atoms in an atomic clock. One second is defined as the time needed for 9192631770 wave cycles to occur.

cesium

In reality, friction or some other energy dissipating mechanism is always present and the amplitude decreases as time passes. This is referred to as _____________ harmonic motion.

damped

The ________________ of an object is the product of the object's mass times its velocity

linear momentum

When a vector is multiplied by -1, the _________ of the vector remains the same, but the ____________ of the vector is reversed.

magnitude, direction

unit of length

meter

The __________ is defined as the distance that light travels in a vacuum in a time of 1/299792458 seconds. This definition arises because the speed of light is a _________________ that is defined to be 299792458 m/s.

meter, universal constant

SI units for speed

meters per second