Name:
Miss Charney
Date:
Physical Science
Motion & Forces Review Sheet
Practice Math Problems:
1. If you walked 20m, took a book from a library table, turned around and walked back to your
seat, what are the distance traveled and displacement?
Distance = 20m + 20m = 40 meters
Displacement = 0 (you ended up where you began)
20 meters
2. Explain why a passenger who is not wearing a safety belt will likely hit the windshield in a
head-on collision.
An object (the passenger) in motion will stay in motion, unless acted on by an unbalanced force
(the windshield).
3. A satellite’s speed is 10,000 m/s. After 1 min, it is 5,000 m/s. What is the satellite’s
acceleration?
𝑣𝑓 − 𝑣𝑖
vi= 10,000m/s
𝑎=
vf= 5,000m/s
𝑎=
t= 1 min = 60 s
a= ?
𝑎 = 60
a = -83.3 m/s2
𝑡
5,000−10,000
60
−5,000
4. Sound travels at a speed of 330 m/s. How long does it take for the sound of thunder to
travel 1485 m?
𝑑
t= ?
𝑠= 𝑡
𝑑
s= 330 m/s
𝑡=
d= 1,485m
𝑡 = 330
t = 4.5s
𝑠
1485
5. Find your mass if a scale on Earth reads 650 N when you stand on it.
m= ?
W = mg
𝑊
W= 650N
𝑚= 𝑔
g= 9.8 m/s2
650
𝑚 = 9.8
m = 66.3kg
6. You weigh yourself at the top of a high mountain and the scale reads 720N. If your mass is
75 kg, what is the acceleration of gravity at your location?
W= 720N
W=mg
𝑊
m= 75kg
𝑔=𝑚
g= ?
720
𝑔 = 75
g = 9.6 m/s2
7. Find the mass of a car that has a speed of 30 m/s and a momentum of 45,000 kg*m/s.
m= ?
p = mv
𝑝
v= 30m/s
𝑚=𝑣
p= 45,000 kg*m/s
45,000
𝑚 = 30
m = 1,500 kg
8. A box being pushed with a force of 85 N slides along the floor with a constant speed. What
is the force of sliding friction on the box?
9. A 10 kg ball is accelerated 500 m/s2 by a force of?
F= ?
F = ma
m= 10kg
F = (10kg)(500m/s2)
a= 500m/s2
F = 5,000N
10. The momentum of a 1500 kg car traveling at a velocity of 10 m/s is?
m= 1,500 kg
p = mv
v= 10m/s
p = (1500kg)(10m/s)
p= ?
p = 15,000 kg*m/s
Are you balanced or unbalanced?:
1)
ANSWER
Unbalanced
30 N to right
20 N
50 N
2)
ANSWER
Unbalanced
85 N to right
50 N
35 N
3)
ANSWER
Balanced
20 N
20 N
4)
How much force by the wall is being exerted
back on the person?
ANSWER
75 N
75 N