PHYSICS 122Y - FINAL EXAM REVIEW
(Use separate paper to define terms and answer questions.)
UNIT 1: Science Habits of Mind
Define these terms:
percent error
accuracy
direct relationship
precision
inverse relationship
1. Which type of graph shows changes or trends over time? Line graph
2. Explain the difference between accuracy and precision using the dartboard example. When playing
darts, accuracy would be hitting the bullseye; precision would be having all of your darts with within the
same general area or having all of your darts hit in the same area
3. When would you use a bar graph? Bar graphs are used to show amounts, such as the number of students
taking biology, physics or chemistry per period
4. Elvis measured the acceleration of his newly developed free-fall toy soldier to be 9.4 m/s2. He took into
account air resistance but still had this value. What is his percentage error for his new toy? The accepted
value (theoretical) for free fall is 9.8 m/s2. Using the equation %error = /exp – theo/ ÷ theo x 100 so /9.49.8/ ÷ 9.8 = 0.0408 x 100 = 4.08%
5. Barnabas placed one inflated balloon in a freezer and another inflated balloon in the sun. The one in the
freezer shrank and the one in the sun expanded. What is the relationship between the temperature of the air
and the volume of the balloon? Direct – as one increases the other increases.
6. When a scientist repeats an experiment multiple times or has multiple trials during an experiment, does
this increase the accuracy or precision of the overall results of the experiment? Explain.
Precision – precision is all about repeatability. The more times it is tested, hopefully his precision is
increased / better.
UNIT 2
KINEMATICS (Linear Motion)
Define these terms:
instantaneous speed
acceleration
displacement
average speed
distance
7. If an object falls in a vacuum, describe its velocity and acceleration. Its velocity will increase but its
acceleration (the rate at which speed changes) will stay the same
8. Describe the speed of an object thrown straight up. As the object goes higher and higher, its velocity
will decrease to zero, then it will fall back down and as it falls its speed will increase until it hits the ground.
On Earth, the speed up and down will change by a factor of 10 m/s per second.
9. In the question above, does the speed of the object ever reach 0? Does the acceleration ever reach 0?
The speed will reach zero at the top (apex) of the object’s path. The acceleration will only be zero when the
object has hit the ground and no longer moving.
10. A car goes from 15 m/s to 30 m/s in 2 seconds. What is the car’s acceleration? 30-15 / 2 = 7.5 m/s2
11. What is the meaning of the slope in a distance vs. time graph? In a velocity vs. time graph? The slope on
a distance-time graph is a measure of the objects speed. For a velocity-time graph the slope represents the
acceleration of the object.
UNIT 3
NEWTON’S LAWS
Define these terms:
law of inertia
Coefficient of friction
friction
static friction
terminal velocity
kinetic friction
12. If a car goes around a curve and starts to hydroplane, what direction will the car travel in? In the
direction that is was going when it started to hydroplane, the direction won’t change.
13. If a 40 N force and a 60 N force act on an object in opposite directions, what is the net force? 60-40 = 20
N
14. If a 30 N force and a 20 N force act on an object in the same direction, what is the net force? 30 + 20 =
50 N
15. A man weighs 95 N. What is his mass? 95/10 = 9.5 kg
16. If the mass of a cart doubles but the force stays the same, what happens to its acceleration? The
acceleration reduces by half
17. Forces always occur in __________________________. pairs
18. A bat hits a baseball (action force). What is the reaction force? The baseball hitting the bat
19. A 150 N object hangs from a container supported by 2 ropes. What is the tension force on each rope?
150/2 = 75 N
20. A bug hits a moving cyclist. Compare the forces exerted on each and the acceleration of each. The force
of impact for the bug is the same as the force of impact for the cyclist. However, because the cyclist has
more mass, the same force has less effect on its acceleration. Yet the bug, with such a small mass will
experience greater acceleration.
21. A push of 50 N on a 20 kg object experiences 10 N of friction. At what rate will the object accelerate?
50-10 / 20 = 2 m/s2
22. For a ball to keep rolling across a floor, must there be a horizontal force acting on it if friction is
present? Explain. Friction opposes motion and will cause an object to slow down. Therefore, if the object
is to keep moving at the same speed, there must be a force (equal to that of the friction force) to keep the
object moving.
23. You push a 5 kg crate across the floor at constant speed. If the coefficient of friction between the crate
and the floor is 0.5, what is the force of friction? Normal force = 5 (10) = 50 N; F = 0.5(50) = 25 N
24. A ball is hit off a tee. If the ball goes from rest to 80 m/s in 1.5 seconds and the ball has a mass of 0.5
kg, what was the force of impact? Ft = mv; F = mv/t = (0.5)(80-0) / 1.5 = 26.7 N
25. How do the coefficients of static and kinetic friction compare to each other? Static friction is larger than
kinetic; it’s harder to get something that’s stationary moving than it is to keep something moving that’s
already in motion.
26. Which is always greater, static or kinetic friction, and why? Static friction is larger than kinetic; it’s
harder to get something that’s stationary moving than it is to keep something moving that’s already in
motion.