FINAL EXAM REVIEW CONCEPTUAL

Question 1

When is the average of an object equal to the instantaneous velocity?

Answer 1

only when the velocity is constant

Question 2

Suppose that an object is moving with a constant velocity. Make a statement concerning its acceleration

Answer 2

The acceleration must be equal to zero

Question 3

An object is moving with constant non-zero acceleration in the +x-axis. The velocity versus time graph of this object

Answer 3

a straight line making an angle with the time axis.

Question 4

A car traveling with velocity “v” is decelerated by a constant acceleration of magnitude “a”. It travels a distance “d” before coming to rest. If its initial velocity were doubled, the distance required to stop would

Answer 4

quadruple

Question 5

Suppose a ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is going up.

Answer 5

Its velocity points upward and its acceleration points downward.

Question 6

From the edge of a roof top you toss a green ball upwards with initial velocity “v0” and a blue ball downwards with the same initial velocity. When they reach the ground below,

Answer 6

the two balls will have the same speed.

Question 7

A student kicks a soccer ball in a high arc toward the opponent’s goal. At the highest point in its trajectory:

Answer 7

neither the ball’s velocity nor its acceleration is zero.

Question 8

For which value of “theta” is the highest of a projectile fired from ground level a maximum?

Answer 8

90 degree above horizontal

Question 9

A projectile is launched with initial velocity “v0” at an angle of 30 degrees above the horizontal. If a second projectile is launched with the same initial velocity but at angle of 60 degrees above the horizontal:

Answer 9

Th ranges of the two projectiles will be identical.

Question 10

When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity. This means that:

Answer 10

the force of air resistance to the weight of the parachutist.

Question 11

A 20-ton truck collides with a 1500-lbs car and causes a lot of damage to the car. Since a lof of damage is done on the car.

Answer 11

the force on the truck is equal to the force on the care

Question 12

A ball is thrown up into the air. At the highest point in its trajectory, the net force acting on it is:

Answer 12

equal to its weight

Question 13

When an object moves at a constant speed on a circular path.

Answer 13

A net force pointing toward the center of the circle acts on the object.

Question 14

Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity:

Answer 14

it is moving in a circle

Question 15

If you push twice as hard against a stationary brick wall, the amount of work you do

Answer 15

remains constant zero

Question 16

You and your friend want to go to the top of the Eiffel Tower. your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy (U) you and your friend, after you both reach the top:

Answer 16

Both of you have the same amount of potential energy.

Question 17

Two blocks o masses “m1” and “m2” are released from the top of two frictionless inclined planes of the same height making 30 degree and 60 degree angles with the horizontal direction, respectively. Which o the blocks is going faster when it reaches the bottom of its respective incline.

Answer 17

Both blocks have the same speed at the bottom.

Question 18

King Kong falls from the top of the Empire State Building, through the air (air friction is present), to the ground below. How does his kinetic energy (K) just before striking the ground compare to his potential energy (U) at the top of the building?

Answer 18

K is less than U

Question 19

You wish to double the speed of a wave in a string by tightening it. By what factor must you increase the tension in the string?

Answer 19

4

Question 20

Sound intensity is defined as:

Answer 20

the sound energy passing through a unit of area per unit time.

Question 21

The sound of 40 decibels is

Answer 21

100 times as intense as the sound of 20 decibels.

Question 22

The reason that you do not observe a Doppler Shift when you listen to the car radio while driving is that:

Answer 22

the source and observer are moving at the same speed.

Question 23

Two cares traveling in the same direction and with the same speed along a straight highway. Does either driver hear a different frequency from the other car’s horn than they would if the cars were stationary?

Answer 23

No, because neither driver experienced a Doppler Shift.

Question 24

Consider an open pipe of length “L”. What are the wavelengths of the three lowest produced by the pipe?

Answer 24

2L, L, 2L/3

Question 25

You walk barefoot in your house and cross from the carpeted living room to the tiled-floor kitchen. The tile floor always feels:

Answer 25

cooler than the carpet

Question 26

When the translation speed of molecules in an ideal gas triples, by what factor does its absolute temperature change?

Answer 26

9

Question 27

A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample?

Answer 27

It does not change.

Question 28

Tow containers of equal volume each hold samples of the same ideal gas. Container A has twice as many molecules as container B. If the gas is the same in the two containers, the correct statement regarding the absolute temperatures “TA” and “TB” in containers A and B, respectively, is

Answer 28

1
TA= /
2TB

Question 29

Phase changes occur

Answer 29

as the temperature remains the same.

Question 30

A monatomic ideal gas is compressed isothermically to one-third of its initial volume. The resulting pressure will be

Answer 30

three times as large as the initial value

Question 31

In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume.

Answer 31

The gas must release heat to its surroundings

Question 32

A Carnot engine operates between absolute temperatures “Th” and “Te”. If “Th” is tripled while “Te” is doubled, the efficiency of this engine will.

Answer 32

increase, but by a factor different from 3/2.

Question 33

An ideal monatomic gas undergoes an isothermal expansion. It is correct to affirm that its entrophy:

Answer 33

increases