1. Review of Projectile Motion, Mass & Weight

2. What is the weight of a 50 kg object near Earth?
Ans. 500 N

3. What is the mass of a 5 kg rock on the Earth?
Ans. 5 kg

4. What is the weight of a 10 kg rock on the Moon? (g = 1.7 m/s2)
Ans. 17 N

5. What is the acceleration?1 2 3 4 5 6 7 8 10 20 30 40 50 60 70 80
Velocity
(m/s)
Time (s)
Ans. 20 m/s2

6. If the object has a mass of 2 kg, what is its weight?1 2 3 4 5 6 7 8 10 20 30 40 50 60 70 80
Velocity
(m/s)
Time (s)
Ans. 40 N

7. What is the displacement for the first 5 seconds?1 2 3 4 5 6 7 8 10 20 30 40 50 60 70 80
velocity
(m/s)
Time (s)
Ans. 75 m

8. A man throws a ball vertically upward
A man throws a ball vertically upward. What is its velocity at its highest point?
Ans. zero

9. A man throws a ball vertically upward
A man throws a ball vertically upward. What is its acceleration at its highest point?
Ans. 10 m/s2 downward

10. A man throws a ball vertically upward with an initial speed of 25 m/s
A man throws a ball vertically upward with an initial speed of 25 m/s. At what time does it return to his hand?
Ans. 5 s

11. A man throws a ball vertically upward with an initial speed of 25 m/s
A man throws a ball vertically upward with an initial speed of 25 m/s. How high does it go?
Ans m

12. What is the displacement for the first 3 seconds?1 2 3 4 5 6 7 8 10 20 30 40 50 60 70 80
Position
(m)
Time (s)
Ans. 60 m

13. What is the acceleration?1 2 3 4 5 6 7 8 10 20 30 40 50 60 70 80
Position
(m)
Time (s)
Ans. zero

14. What is the weight?
45 kg
Ans. 450 N on Earth

15. Planet X has an acceleration due to gravity of 0. 1 m/s2
Planet X has an acceleration due to gravity of 0.1 m/s2. Joe can jump 1 m vertically on Earth. How high can he jump on Planet X?
Ans. 100 m

16. Planet X has an acceleration due to gravity of 0. 1 m/s2
Planet X has an acceleration due to gravity of 0.1 m/s2. Joe has a mass of 55 kg on Earth. What is his mass on Planet X?
Ans. 55 kg

17. Joe can lift a mass of 136 kg on Earth. How much weight is he lifting?
Ans N

18. Planet X has an acceleration due to gravity of 0. 1 m/s2
Planet X has an acceleration due to gravity of 0.1 m/s2. Joe can lift a mass of 136 kg on Earth. How much mass can he lift on Planet X?
Ans kg

19. Planet X has an acceleration due to gravity of 0. 1 m/s2
Planet X has an acceleration due to gravity of 0.1 m/s2. Joe’s workout set of weights has a mass of 200 kg. What is the weight of the set on Planet X?
Ans. 20 N

20. The next four slides deal with the same initial information.

21. What is the initial vertical velocity of the object?
30 m/s
50
Ans. 23 m/s

22. What is the time in the air from launch to landing at same height?
30 m/s
50
Ans. 4.6 s

23. What is the maximum height reached by the object?
30 m/s
50
Ans m

24. What is the range for this projectile?
30 m/s
50
Ans m

25. The following two slides are based on the same initial information.

26. What is time in air?
15 m/s y x
2 m Dx
Ans s

27. What is Dx?
15 m/s y x
2 m Dx
Ans. 9.5 m

28. The following three slides have the same initial information.

29. How long will it take boat to cross river?
6 km
12 km/h B
4 km/h
Ans. ½ h

30. How far downstream will the boat drift?
6 km
12 km/h B
4 km/h
Ans. 2 km

31. What is the velocity of the boat relative to the shore?
6 km
12 km/h B
4 km/h
Ans  SE