Physical Science Homework Problems
Richard Goode
PHSC P112
Chapter 2 Motion
1. What is the average speed of car that travels 184 km in 2.3 hours?
v = 80 km/h
2. What is the average speed of a car that travels 35 km in 20 minutes?
v = 105 km/h
3. How long will it take a canon ball traveling at 300 m/s to reach a target 1500 m away?
t=5s
4. Light travels at a speed of 3 x 108 m/s in space. If on a given day it takes 3.2 minutes for a radio
signal to travel from Mars to the Earth, how far apart are the two planets at this time?
d = 5.76 x 1010 m
5. If the speed of sound is 340 m/s and you hear thunder 5.5 seconds after you see the flash, how
far away was the lightening?
d = 1870 m
6. A car travels for 3 hours at 75 km/h and then at 100 km/h for the next hour. What is the average
speed of the car for the entire trip?
v = 81.25 km/h
7. What is the average acceleration of a truck that accelerates from rest to 25 m/s in 10 seconds?
a = 2.5 m/s2
8. How long will it take a car to accelerate from 5 m/s to 15 m/s with an acceleration of 2.5 m/s2?
t=4s
9. How far will a car travel if it accelerates from rest at 2.7 m/s 2 for 25.7 seconds?
d = 892 m
10. How far will a car travel if it accelerates from 4.5 m/s at 2.7 m/s 2 for 25.7 seconds?
d = 1007 m
11. What is the weight of a 65 kg person on earth?
F = 637 N or 637 kg m/s2
12. What force is needed to accelerate a 3.7kg bicycle at 2.8 m/s2?
F = 10.4 N or 10.4 kg m/s2
13. What would be the acceleration of a 2.0 kg toy car when an unbalanced force of 3.7 N is applied?
a = 1.85 m/s2
14. What is the acceleration of a car that slows from 28 m/s to 6 m/s in 4.2 s?
a = -5.3 m/s2
15. A ball travels straight up for 4s before falling. What was the original speed of the ball?
v = 39 m/s
16. A rock is dropped into a well and you see it hit the water 6s later. How deep is the well? What
was the speed of the rock as it hit the water?
d = 176 m
vf = 59 m/s
17. What is the momentum of a 120kg football player traveling at 9m/s?
p = 1080 kg m/s
18. An airplane weighing 27355N is traveling at 75m/s. What is the airplane’s momentum?
p =209,349 kg m/s
19. A 250 kg cannon fires a 2 kg cannonball at 300 m/s. What is recoil velocity of the cannon?
v = 2.4 m/s
20. An astronaut and equipment weigh 4410N on earth. While weightless in space, the astronaut
throws a 25kg bag of tools at 5m/s. What is the resulting velocity of the astronaut?
v = 0.28 m/s
21. A 2500kg airplane accelerates from 70 m/s to 110 m/s in 25s. What is the force on the airplane?
F = 4,000 N
22. What is the centripetal acceleration of a 1.2kg ball on the end of a 1.3m string traveling at 2.4
m/s? What is the centripetal force?
ac = 4.43 m/s2
Fc = 5.32 N
Thought Questions
1.
2.
3.
4.
5.
6.
Can gravity act in a vacuum? Explain
Is it possible for your car and a fully loaded truck to have the same momentum? Explain.
Can your weight change if your mass remains a constant? Explain.
Describe how a rocket blasting off from the earth works.
Describe the motion of a ball dropped from a moving car.
A father and his 8 year old son are on very slick ice. They face each other put their hands
together and push. Describe what happens.