Velocity, Acceleration, and Newton’s Laws Test Review



Velocity, Acceleration, and Newton’s Laws Test Review

1. What is speed? distance over a specific period of time

2. What is velocity? the speed in a certain direction

3. What is the average speed (velocity)? speed (velocity) that does not change

4. What is the formula for Momentum? mom= mass X velocity

5. Solve the following Momentum Problems:

a. What is the momentum of an object that has a mass of 72 grams and a velocity of 37 m/sec? (mass must be in kilograms) 72 g X 1 kg = .072kg

1 X 13 g

.072 kg X 37 m/sec = 2.664 ~ 2.7 N

b. What is the velocity of an object with a momentum of 60 N and a amass of 12 grams?

12 g X 1 kg = .012 kg 60 N/.012 kg = 5000 m/sec

1 X 13 g

6. What is an example of a unit for velocity? speed? force? m/sec; m/sec; N

7. What are the three types of acceleration? What “sign” would you give to speeding up? What “sign” would you give to slowing down? speed up, slow down, change direction; +; -

8. What causes velocity to change? a net force is applied

9. What is a net force? the combination of all forces acting on an object

10. What is balanced force (use tug-of-war as an example)? forces that are equal and moving in opposite directions (tug of war where both sides are pulling away with equal strength and the flag does NOT move)

11. What is an unbalanced force (use tug-of-war as an example)? forces that are NOT equal and moving in opposite directions (tug of war where both sides are pulling away with unequal strength and the flag moves in one direction).

12. What is friction? How does it “move” in regards to a moving object? a slowing force; it move opposite of the motion of a moving object

13. As objects move further apart, what happens to the gravitational pull? it decreases

14. State Newton’s 1st Law. Give an example. Objects at rest tend to stay at rest; objects in motion tend to stay in motion (a car hits a tree and the driver flies out through the windshield)

15. State Newton’s 2nd Law. Solve the following problems using Newton’s 2nd Law.

Force= mass X acceleration

a. What is the force applied to a 20 kg object that accelerates to 30 m/sec? 20 kg X 30 m/sec= 600 N

b. What is the acceleration of an 86 kg object that has a force of 68 N? 68 N/86 kg= .791 m/sec2 ~ .79 m/sec2

16. What is Newton’s 3rd Law? Give an example. For every action there is an equal and opposite reaction; a rocket will only fly up depending on the amount force that is pushing the object in the opposite direction

17. What is freefall? What is the weight of an object during freefall? an object falling to the earth pulled on by the force of gravity; zero (objects are weightless during freefall)

18. As gravity is pulling a person in a parachute down to the Earth, what is pushing up against the underside of the parachute? air resistance

19. What is the value of acceleration due to gravity (g) in a free falling object? Solve the following Velocity of Freefalling objects problems:

9.8 m/sec2

a. What is the velocity of an object in freefall that falls for 780 seconds?

Velocity= 9.8 m/sec2 X 780 seconds= 7644 m/sec

b. How long does an object in freefall descend if it is falling at a velocity of 600 m/sec?

600 m/sec/9.8 m/sec2 = 61.22 ~60 sec

20. Why does a loaded truck take longer to stop than an empty truck? the loaded truck has more mass and therefore has more momentum which will require more force to stop

21. Can momentum be transferred from one object to another? yes

22. What is centripetal force? the force of a revolving object pulling it toward the center

23. What is acceleration? the rate of change of velocity (or a change in velocity)

Solve the following problems:

a. What is the acceleration of an object that increases velocity from 35 m/sec to 45 m/sec in 2 seconds?

(45 m/sec- 35 m/sec)/2 seconds= 5 m/sec2

b. What is the ending velocity of an object (beginning speed is at rest) that has an acceleration of 50 m/sec2 and accelerates in 4 seconds?

50 m/sec2 X 4 seconds= 200 m/sec

24. What is the difference between speed and velocity? velocity includes direction

Solve the following velocity problems:

a. What is the velocity of an object that travels 5 meters in 2 seconds?

5 m/2 sec= 2.5 m/sec ~ 3 m/sec

b. How far does an object travel at a velocity of 25 m/sec for 25 seconds?

25 m/sec X 25 sec = 625 meters

c. How long does it take a car to travel 50 meters if it has a velocity of 50 m/sec?

50 meters/ 50 m/sec= 1 sec

25. Which has more inertia: a tennis ball or bowling ball? bowling ball A tossed baseball or a thrown baseball? thrown baseball

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