**CONCEPTUAL PHYSICS: Major Test Chapter 2 KEY**

**N.B.**** The TEST ID of this test may not be the
same as the TEST ID of the test you took.**** **

**PART I: Multiple
Choice (45)**

*Choose the best option
to complete each statement or answer each question below. Carefully mark your scantron
answer document.*

1) When you look at the speedometer in a moving car, you can see the car's __________.

A) instantaneous speed B) average speed C) instantaneous acceleration D) average acceleration

2) A ball is thrown straight up. At the top of its path its acceleration is __________.

A) 0 m/s to power of (2) B) about 5 m/s to power of (2) C) about 10 m/s to power of (2) D) about 20 m/s to power of (2)

3) In the absence of air resistance, objects fall at constant __________.

A) acceleration with each successive second B) distance with each successive second

C) speed with each successive second D) velocity with each successive second

4) As an object falls freely in a vacuum, its __________.

A) velocity remains constant B) acceleration increases C) velocity and acceleration increase D) acceleration remains constant

5) A car accelerates at 2 m/s to power of (2). Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30 m/s?

A) 2 seconds B) 15 seconds C) 30 seconds D) 60 seconds

6) When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration __________.

A) depends on launch speed B) depends on launch direction C) can be greater than g D) is always g

7) Suppose you take a trip that covers 240 km and takes 4 hours to make. Your average speed is __________.

A) 30 km/h B) 60 km/h C) 120 km/h D) 340 km/h

8) Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. Which of the following is true?

A) Your speed is changing B) Your velocity is constant C) Your acceleration is changing D) Your acceleration is constant

9) If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first?

A) The coin B) The feather C) Neither, there is no gravity in a vacuum D) Neither, they will both reach the bottom at the same time

10) A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be __________.

A) more than the speed it had when thrown upwards B) less than the speed it had when thrown upwards C) the same as the speed it had when thrown upwards D) The same as its acceleration

11) An object travels 8 meters in the first second of travel, 8 meters again during the second second of travel, and 8 meters again during the third second. Its acceleration is __________.

A) 0 m/s to power of (2) B) 4 m/s to power of (2) C) 8 m/s to power of (2) D) 16 m/s to power of (2)

12) If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by __________.

A) about 5 m/s B) about 10 m/s C) about 15 m/s D) a rate that depends on its initial speed

13) Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration?

A) 5 km/h s B) 10 km/h s C) 35 km/h s D) 40 km/h s

14) A ball is thrown straight up with an initial speed of 10 m/s. At the top of its path its instantaneous speed is __________.

A) 0 m/s B) 5 m/s C) 10 m/s D) 20 m/s

15) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always __________.

A) in the direction of motion B) opposite its velocity C) directed upward D) directed downward

**PART II: True False
(30)**

*Determine whether the
statements below are true or false. Mark
'A' for true and 'B' for false.*

**PART III: Rewrite
(60)**

*On your own paper
rewrite each false statement so that they will be true. Be sure to address all the areas that are
false. You will receive 10 points for
each correctly rewritten statement. The rewritten false statements should be
the only information on this paper.*

16) Average speed can be defined as the total time it takes for a trip divided by the total distance.

17) As a ball falls freely, the acceleration each second is the same as the acceleration the second before or the second after.

18) The rate at which velocity or direction changes during a time interval time is called acceleration.

19) Acceleration means only that something is changing its speed.

20) Velocity and speed are not exactly the same thing because, while both tell how fast something is going, velocity also tells you the direction.

21) A p-t graph of constant velocity has a line with an infinite number of slopes.

22) The slope of the line on a p-t graph tells you velocity, and the slope of the line on a v-t graph tells you acceleration.

23) A ball is thrown into the air. At the highest point both the velocity and the acceleration are zero.

24) The SI unit of velocity is the meter-second

25) When a car rounds a corner at a constant velocity, its acceleration is zero.

**PART IV Short Answer
(30)**

*Answer the questions
below on a separate sheet of paper. Be
sure that your answers are in complete sentences. The only thing on this paper should be the
answers to these three questions and nothing else.*

26) Why does time enter twice the SI unit for acceleration?

27) Explain how it is possible to accelerate without changing speed.

28) If the line on a p-t graph is curved, what is the object doing? How would this same kind of motion look on a v-t graph? Sketch both graphs and label everything.

**PART V Problems (40)**

*Solve the problems
below on your own paper. Be sure that
there is only one problem on each page. Since this section has four problems
you should have four pages for this part of your test. You will receive credit
based on how well you demonstrate your ability to follow the 3-column-method
(A.K.A. the GPSM). N.B.
Even if all you can do is column 1 you will receive at least 1/3 credit for
that effort.*

29) What is the acceleration of a car that goes from rest to 90 km/h in 6.0 seconds?

30) A stone is dropped from a 100m high cliff. How long will it take to hit the ground below?

31) What is the velocity of a cheetah that runs 130 m in 8.0 s?

32) If you drop a stone down a deep well and 3.7 seconds later you hear it splash in the water how deep must the well be? (Ignore the time it takes for the sound to travel up the well.

**CONCEPTUAL PHYSICS: Major Test Chapter 2 KEY**

**N.B.**** The TEST ID of this test may not be the
same as the TEST ID of the test you took.**** **

**PART I: Multiple
Choice**

1) Answer: A

2) Answer: C

3) Answer: A

4) Answer: D

5) Answer: B

6) Answer: D

7) Answer: B

8) Answer: D

9) Answer: D

10) Answer: C

11) Answer: A

12) Answer: B

13) Answer: A

14) Answer: A

15) Answer: D

**PART II PART III:
True False and Rewrite**

16) Answer: FALSE

TRUE: Average speed can be defined as the total distance of a trip divided by the total time it takes for a trip

17) Answer: TRUE

18) Answer: TRUE

19) Answer: FALSE

TRUE: Acceleration means that something is changing its speed or its direction or both.

20) Answer: TRUE

21) Answer: FALSE

TRUE: A p-t graph of acceleration has a line with an infinite number of slopes.

OR: A p-t graph of constant velocity has a line with only one slope.

22) Answer: TRUE

23) Answer: FALSE

TRUE: A ball is thrown into the
air; at the highest point the velocity is zero but the acceleration is still
9.8 m/s^{2}.

24) Answer: FALSE

TRUE: The SI unit for velocity is the m/s or the km/h.

25) Answer: FALSE

TRUE: When a car rounds a corner at a constant velocity, its acceleration is not zero because the car is changing direction.

**PART IV: Short Answer**

26) Answer: Time enters twice in the SI unit for acceleration because it is used once for the time it takes to change position and again for the time it takes to change velocity.

27) Answer: Since acceleration means that an object is either changing speed or changing direction it is possible to accelerate without changing speed by simply changing direction.

28) Answer: If the line on a p-t graph is curved, the object is accelerating. On a v-t graph this would look like a diagonal line moving up and to the right. Here is a sketch of what the graph should look like:

This is a v-t graph of an object that is accelerating:

This is a p-t graph of an object that is accelerating:

**PART V: Problems **

29) Answer:

a = ? km/h a = vf - vi / t a = 90 km/h - 0 km/h / 6.0 s

vi = 0 km/h a = 90 km/hr / 6.0 s

vf = 90 km/h a = 15 km/hdotmaths

t = 6.0 s

30) Answer:

a
= 10m/s^{2} d
= 1/2at^{2 }

t = ?s

d = 100m ^{ }

31) Answer:

d = 130 m v = d/t v = 130 m/8.0 s

t = 8.0 s v = 16.25 m/s

v = ? m/s

32) Answer:

t = 3.7 s d = 1/2 at^{2} d
= 1/2 10 m/s^{2} (3.7s)^{2}

a = 10 m/s^{2} d
= 5m/s^{2} x 13.69 s^{2}

d = ? m d = 68.45 m