U4 Review Worksheet
Vocabulary
A. friction / F. vector / K. weight / P. net forceB. unbalanced, outside force / G. inertia / L. force / Q. action reaction forces
C. freebody diagram / H. mass / M. same
D. air resistance / I. accelerated / N. Newton
E. normal / J. scalar / O. direction
1. A change in a object’s state of motion is cause by a(n) ______
2. In the metric system, forces are measured in units called ______
3. The property of an object which causes it to resist changes in motion is _____
4. The interaction between 2 objects is a ______
5. When an unbalanced force acts on an object, it is ______
6. Acceleration of an object varies directly with applied force and inversely with ____
7. The measurement of gravitational force on an object is ______
8. The sum of all forces acting on an object is ______
9. Mass and speed are examples of _____ quantities
10. Acceleration and force are examples ______quantities
11. The force that opposes motion is ______
12. Although ______forces have the same magnitude and act in opposite directions, they do not cancel
each other since they act on different objects.
13. A graphical technique of showing all the forces acting on an object is ______
14. An object accelerates if there is a change in its rate of motion or _____ of motion
15. Claire says that if an object has no acceleration, then no forces are acting on it. Connordoesn't
agree, but can't provide an explanation. They both look at you. What do you say?
16. If a mosquito and a car windshield collide, which decelerates more, the mosquito or the car
windshield? Is the force different on the mosquito or the windshield?
17. After canoeing on a lake, I return to the dock. I step off a canoe onto a dock. When I turn around,
the canoe is moving away from the dock out toward the lake. Explain what happened.
18. If an object has a net force of zero on it, is it at rest? Explain.
19. Using the diagram above, if all the forces are equal, what is the net force on the object?
- If the object above is moving to the left, which force would represent the direction ofthe net force on the object?
- If the object were sitting on a table, which force would represent the support force?
- If the object were moving to the left, which force would represent the force offriction?
20. A 400 N cargo crate is lifted onto a freight ship by a four cables. What is the size of the tension in
each cable (remember standing on 2 scales)?
21. A 500 lb piano must be lifted to the third floor of a building. The movers have plenty of thin rope
that will support 100 lbs. How can they lift the piano and be sure that it will not fall?
22. What is the net force on the object below? What is its acceleration?
23. What is the net force on the object below? What is its acceleration?
24. What is the net force on the object below? What is its acceleration?
25. What is the net force on the object below. What is its acceleration?
26. What is the weight in newtons of a 90-kg person?
27. A person weighs 660 Newtons. What is their weight in newtons?
28. You observe an ice hockey puck moving across a frictionless icy surface at a constant speed of
1.5 m/s.
a. Draw a force diagram of this situation.
b. Take a look at your force diagram, think about Newton’s Laws of motion, and explain what force is
causing the hockey puck to move across the frictionless surface.
c. If the hockey puck were to leave the frictionless surface and move unto a concrete surface, draw a
force diagram of the hockey puck as it moves across the concrete surface.
d. What would eventually happen to the hockey puck, once it is moving across a concrete surface?
Explain.
29. A 50 kg girl is standing on a bathroom scale.
a. Calculate her weight.
b. What is the cause of her weight? Explain.
c. Where could she go to become weightless? What would happen to her mass? Explain.
30. Boxes are shown below with various masses on a friction-free table. Arrows are not to scale.
Find the net force on each. Rank them in order from greatest to least.
Find the accelerations ofthe boxes. Rank them from greatest to least.