1. Forces Review Sheet

2. Does the law of inertia pertain to moving objects, resting objects or both? Explain.
Both, objects in motion stay in motion, objects at rest stay at rest, unless acted upon by an outside unbalanced force.-Newton's first Law, the Law of inertia.

3. The law of inertia says an object in motion stays in motion, then why do you have to keep pedaling for your bike to maintain its speed?
The Law of Inertia states that an object in motion stays in motion and an object at rest stays at rest unless acted upon by an outside force. Frictions is one of those forces that stops an object in motion. One must continue pedaling to overcome friction.

4. If a cannon ball was shot in frictionless space, what force would be needed to keep it in motion? Explain.
No force, due to Newton’s first Law the Law of Inertia.

5. What is meant by the net force that acts on an object?
Net force is all the forces as opposed to single forces such as Fg alone

6. A cart is being moved by a certain net force
A cart is being moved by a certain net force. If the net force is doubled, what happens to the acceleration? If a load is put in the cart doubling its mass, what happens to the acceleration?
Acceleration will double when net force is doubled. Acceleration will decrease by half when mass is doubled.

7. Directly proportion= they do the same
What is the difference between directly proportional and inversely proportional?
Directly proportion= they do the same
Inversely proportional= they do the opposite
F=ma
Variables on opposite sides of equations, like “F” and “a” or “F” and “m”, will do the same thing such as increase or decrease. They are directly proportional.
Variables on the same sides of an equation, like “m” and “a” will do the opposite of each other. If one increases the other decreases. They are inversely proportional.

8. If an object has no acceleration, does that mean that no forces are acting on it? Explain.
No, Balanced forces may be acting on the object. On Earth, Gravity is always acting on objects.

9. When swimming, a person pushes the water backward
When swimming, a person pushes the water backward. What is the reaction to this action?
Water pushed the person forward

10. The force of gravity on a 2 kg object is twice what it is on a 1 kg object. Why doesn’t the 2 kg object fall with twice the acceleration?
Gravity is the same for all objects.

11. A ball is placed in back of a truck
A ball is placed in back of a truck. What happens to the ball when the truck accelerates forward? Why? What Law of Motion is this an example of?
Objects at rest stay at rest so the ball stays where it is while the truck move's below it causing the ball to hit the tailgate( appear to move backwards) Newton’s first Law  

12. Draw a Free-Body diagram for each of the following scenarios:
A ball falls with air resistance
A helicopter lifts off the ground
2 lineman hit into each other

13. A fork has some cake on it
A fork has some cake on it. There is an upward force of 12 N on the fork. Gravity is exerting 9 N of force. What is happening to the fork? What is the Σ F? Draw a Force Diagram to illustrate.

14. What is weight? How can you find it?
Weight is mass affected by gravity. You can determine it by m × g and g = 9.8 or round to 10m/s/s

15. What is Newtons’ 2nd law?
F=ma

16. If Velocity is constant, what is acceleration? ƩF?