SACE Stage One
Physics
CHAPTER 2: TOPIC TEST
SECTION A: Multiple Choice
20 marks
SECTION B: Essay Questions
10 marks
SECTION C: Computational Questions
20 marks
Total: 50 marks
Instructions to Candidates:
1.
Answer Section A on the Multiple-Choice Answer sheet. Make sure your name and
the name of your Physics teacher are included on this sheet and your script
booklet.
2.
Answers in Section C must show logic and clear reasoning. Remember to clearly
indicate your answer and don’t forget units.
Page 1
SECTION A: MULTIPLE CHOICE QUESTIONS
(20 Marks)
Choose the best answer to each question.
1.
a)
b)
c)
d)
e)
2.
a)
b)
c)
d)
e)
3.
a)
b)
c)
d)
e)
4.
a)
b)
c)
d)
e)
5.
a)
b)
c)
d)
e)
6.
a)
b)
c)
d)
e)
Speed is
a measure of how fast something is moving.
the distance covered per unit time.
always measured in terms of a unit of distance divided by a unit of time.
all of the above
none of the above
When you look at the speedometer in a moving car, you can see the car’s
instantaneous speed.
average speed.
instantaneous acceleration.
average acceleration.
average distance travelled.
Suppose you take a trip that covers 240 km and takes 4 hours to make. Your average speed is
960 km/h.
480 km/h.
240 km/h.
120 km/h.
60 km/h.
Acceleration is defined as the CHANGE in
distance divided by the time interval.
velocity divided by the time interval.
time it takes to move from one speed to another speed.
time it takes to move from one place to another place.
velocity of an object.
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?
5 km/h/s
10 km/h/s
35 km/h/s
40 km/h/s
45 km/h/s
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s.
about 5 m/s.
about 10 m/s.
about 20 m/s.
about 50 m/s.
Page 2
7.
a)
b)
c)
d)
e)
8.
a)
b)
c)
d)
e)
9.
a)
b)
c)
d)
e)
10.
a)
b)
c)
d)
e)
11.
a)
b)
c)
d)
e)
12.
a)
b)
c)
d)
e)
A ball is thrown straight up. At the top of its path its acceleration is
0 m/s/s.
about 5 m/s/s.
about 10 m/s/s.
about 20 m/s/s.
about 50 m/s/s.
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
0 m/s/s.
8 m/s/s.
16 m/s/s.
32 m/s/s.
none of the above
Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car’s average
acceleration?
0.25 m/s/s
2.5 m/s/s
4.0 m/s/s
10 m/s/s
40 m/s/s
A car accelerates at 2 m/s/s. Assuming the car starts from rest, how much time does it need to
accelerate to a speed of 30 m/s?
2 seconds
15 seconds
30 seconds
60 seconds
none of the above
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase
each second by
about 5 m/s.
about 10 m/s.
about 15 m/s.
a variable amount.
a rate that depends on its initial speed.
In the absence of air resistance, objects fall at constant
velocity.
speed.
acceleration.
distances each successive second.
all of the above
13. 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.
Page 3
14. Ten seconds after starting from rest, a freely falling object will have a speed of about
a)
b)
c)
d)
e)
10 m/s.
50 m/s.
100 m/s.
500 m/s
more than 500 m/s.
15. Suppose an object is in free fall. Each second the object falls
a)
b)
c)
d)
e)
with the same average speed.
with the same instantaneous speed.
the same distance as in the second before.
a larger distance than in the second before.
none of the above
16. 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-they will both reach the bottom at the same time.
17. If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting point is
about
a) 1 second.
b) 2 seconds.
c) 10 seconds.
d) 20 seconds.
e) not enough information to estimate.
18. Consider drops of water leaking from a water faucet. As the drops fall they
a) get closer together.
b) get farther apart.
c) remain at a relatively fixed distance from each other.
19. 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.
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) varies with body orientation.
c) is usually greater for taller players (but not always).
d) depends on all the above
e) is g; no more, no less.
20.
Page 4
SECTION B: ESSAY QUESTIONS
(10 Marks)
1. Write a short paragraph explaining the difference between speed and velocity, and give
examples of both
(3 Marks)
Speed is the rate at which an object covers distance. Velocity is speed in a direction. When you get
in a car and travel on a highway at 90 km/h, this is your speed. If you are travelling south, then
your velocity is 90 km/h South.
2. Write a short paragraph explaining what acceleration is and why a car is accelerating as it
rounds a corner.
(2 Marks)
Acceleration is the rate of change of velocity. Since velocity has both speed and direction, if the
direction of a moving object changes, as in rounding a corner, then the object is accelerating.
3. Comment on the graph below: describing the motion it represents
(a) in words
The object starts from rest (v0 = 0 ms-1) and increases its speed at a constant rate. The acceleration
is constant and is equal to the gradient of the line. a = 10 ms-2.
(b) and the information provided by equation of the straight line.
(the function on the X or horizontal axis)
Y = MX+C
(Y –intercept)
(gradient = Y-step/X –step)
(the function on the Y or vertical axis)
v = 10 t
-1
Velocity (m.s )
50
40
30
20
10
0
0
1
2
3
4
5
T im e ( s )
(5 Marks)
Page 5
Section C: Computational Questions
1.
(20 Marks)
What is the average speed of a car the travels 45 metres in 5 seconds.
distance = 45 m
time = 5 s
average speed = 45 / 5 = 9 ms-1.
(3 marks)
2.
What is the acceleration of a vehicle that travels at a steady speed of
10 m s-1 for 10 seconds?
No change in speed, then no acceleration.
(1 marks)
3.
(a) What will the speed of a coin dropped from a building be at the end of
8 seconds.
t=8s
How Fast
g = 10 ms-2
v = g t = 10 × 8 = 80 ms-1
(b) How far will it have travelled at the end of this time.
( Use the acceleration due to gravity =10 m s-2 )
How Far
distance = ½ g t2 = ½ 10 82 =320 m
( 4 marks)
Page 6
-1
4. A jet-powered car starts from rest and reaches a speed of 9 ms in 3 seconds.
Find:
a) the acceleration of the car.
v0 = 0 ms-1
v = 9 ms-1
a = ∆v / ∆ t
= (v - v0) / ∆ t = 9 / 3 = 3 ms-2
t=3s
b) the average velocity over three seconds.
average velocity = (v0 + v) / 2 = 0 + 9 / 2 = 4.5 m
c) the distance travelled by the car in three seconds.
distance = ½ a t2 = ½ 3 32 =13.5 m
average velocity = distance / time
distance = 4.5 × 3 = 13.5 m
OPTIONS How Far
(4 marks)
5. A coin is dropped from the side of a tall building
Assuming the acceleration due to gravity is 10 ms-2 and there is negligible air friction.
What is
a) the final velocity that the coin reaches just before it reaches the ground, if it fell
for 3 seconds.
t=3s
g = 10 ms-2
How Fast v = g t = 10 × 3 = 30 ms-1
b) the height of the building.
How Far
distance = ½ g t2 = ½ 10 32 =45 m
(4 marks)
-1
6. After starting from rest a car has a final speed of 15 m s after travelling for 5 seconds.
v0 = 0 ms-1
v = 15 ms-1
t=5s
a) What is the average speed over the 5 second interval?
average velocity = (v0 + v) / 2 = 0 + 15 / 2 = 7.5 m
b) What is the acceleration of the car?
a = ∆v / ∆ t
= (v - v0) / ∆ t = 15 / 5 = 3 ms
Page 7
-2
(4 marks)