1. Forces--Review

2. Newton’s Laws of Motion:
1st Law(Law of Inertia)—an object at rest stays at rest and an object in motion stays in motion unless acted on by some unbalanced force. 2nd Law(Law of Acceleration)—relates force, mass, and acceleration in the equation.. F = m x a 3rd Law—For every action, there is an equal but opposite reaction.

3. Which of Newton’s Laws?
2nd Law?
3rd Law?
1st Law?
1st—Yes, Man is not wearing seatbelt, therefore he is moving and keeps moving!! Best Answer!!
2nd—Possibly. Could be referring to the force applied to the cars mass to cause it to stop!
3rd—No. This is not the Action-Reaction Newton referred to in his 3rd law.

4. Which of Newton’s Laws?
3rd—Rocket goes one way, gasses move the other way!!

5. Which of Newton’s Laws is shown in the video clip below?
3rd—Rocket goes one way, gasses move the other way!!

6. Which of Newton’s Laws?
1st—Yes, Man is not wearing seatbelt, therefore he is moving and keeps moving!! Best Answer!!
2nd—Possibly. Could be referring to the force applied to the motorcycle’s mass to cause it to stop!
3rd—No. This is not the Action-Reaction Newton referred to in his 3rd law.

7. Which of Newton’s Laws? A) 1st B) 2nd C) 3rd D) 4th
1st—Yes, ladder is not strapped down, it is moving with the truck and keeps moving!! Best Answer!!
2nd—Possibly. Could be referring to the force truck applies to car to accelerate it.
3rd—No. This is not the Action-Reaction Newton referred to in his 3rd law.

8. Which of Newton’s Laws? A) 1st B) 2nd C) 3rd D) 4th
1st—???? It’s a stretch, but possibly balls changing their motion when unbalanced force is applied!
2nd—???—Force of balls = mass of balls x acceleration of balls.
3rd—Best Answer—Action/Reaction
A) 1st B) 2nd C) 3rd D) 4th

9. Balanced or Unbalanced? Find the Net Force
If forces are same size, opposite direction, then balanced.
Net force = 0
FNet = 0 N

10. Balanced or Unbalanced? Find the Net Force
If forces are different size and/or opposite direction, then unbalanced.
Opposite direction, so subtract.
FNet = 50 N left

11. I’m the Man!!
Let’s try and put what you know about balanced and unbalanced forces together with my 2nd law of motion.
Sir Isaac Newton—

12. Solve for the unknown:
Fnet = 10 N right
m = 5 kg
a = ?

13. Solve for the Unknown:
FNet = 40 N Left
m = ?
a = 4 m/s/s left

14. Solve for the Unknown: Which force is bigger? Right How much bigger?
m = 10 kg
a = 3 m/s2 Right
Which force is bigger?
Right
How much bigger?
use F = ma
25 N + 30 N = 55 N

15. Solve for the Unknown: Which force is bigger? Left How much bigger?
m = 6 kg
a = 4 m/s2 left
Which force is bigger?
Left
How much bigger?
use F = ma
80N – 24 N = 56 N

16. Solve for the Unknown in the following diagram:
22 m/s/s left
6 m/s/s left
5 m/s/s left
4 m/s/s left

17. Solve for the Unknown in the following diagram:
20 kg
12 kg
8 kg
4 kg

18. Solve for the Unknown in the following diagram:
50 N right
50 N left
20 N right
120 N right

19. Solve for the Unknown in the following diagram:

20. Besides formulating his 3 laws of motion, What else did Newton do??
Johannes Kepler
It’s Story time

22. Newton’s Law of Universal Gravitation
Any 2 objects have a force of attraction between them, the size of which depends on 2 things:
Mass of the object(direct relationship).
The larger the mass, the larger the force of attraction.
The distance between the objects(inverse relationship).
The greater the distance between the two objects, the smaller the force of attraction.

24. Which of the following pairs has the greatest force of attraction?
A B

25. Which of the following pairs has the greatest force of attraction?
A B