Newton's laws practice problems

1. Describe each of Newton's 3 laws.

2. A 2 kg toy car is pushed with a 40 newton force. What is the car's acceleration?

3. Without calculating anything, what would be the effect (in problem 2) of increasing the mass of the car?

4. Give an example of Newton's 1st law in action.

5. Give an example of Newton's 3rd law in action.

6. Newton's "big book", what I claim is the most important non-religious book of all time is _____ and was published in _____.

7. Distinguish between weight and mass.

8.   What is the SI unit of force?  What is the English unit of force?

9.  How does weight depend on gravitational acceleration?

10.   Freefall review.  Consider a ball falling from rest.  How fast would it be moving after 4 seconds?  How far would it fall in this time?


Answers:

1.  See notes.

2.  40 / 2 = 20 m/s/s

3.  lower acceleration

4.  See notes.  Tablecloth pull, etc.

5.  firearm recoil, etc.

6.  Principia Mathematica, 1687.

7.  mass - the amount of stuff (in kg); weight - the gravitational pull on this stuff (in newtons).  The weight depends on where you are (in terms of how the gravitational acceleration changes).  For example, your weight on the Moon is 1/6 that of Earth.

8.  newton; pound

9.  W = m g.  Weight is depending on the local value of g.  Compared to your normal Earth weight, more g means more weight; less g means less weight (like on the Moon).

10.  Letting g = 10 m/s/s -->  40 m/s, 80 m

This is using the equations:

Vf = g t
d = 0.5 g t^2

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