1. The Nature of Force

2. What is a Force? Force = a push or a pull.
You exert a force on a:
pen when you write
Book when you lift it
Zipper when you pull it
Described by how strong the force is and in what direction it acts.

3. Net Forces
The overall force on an object after all the forces are added together.
Unbalanced Forces
Add together
Move an object in a positive direction
Subtract from each other
Slow an object down
Balanced Forces
Cancel each other
Completely stop all movement
Balanced and Unbalanced Forces - BrainPop

4. Unbalanced Forces
Unbalanced forces cause an object to start moving, slow down or change direction.
Change an object’s motion or acceleration.
Same Direction: the net force
is the sum of the two individual
forces. The arrow will move to
the right.
B. Opposite Direction: the net force
is the difference between the
two forces. The arrow will move
in the direction of the greater force.

5. Balanced Forces
Balanced forces are equal forces acting on one object in opposite directions.
Does Not change the object’s motion or acceleration but completely stops all motion or acceleration!
Two equal forces in opposite
directions, cancel each other out.
The arrows don’t move.

6. Determining Net Forces
Balanced or Unbalanced 3. 4.

7. Determining Net Forces-5 10 5 5.
Balanced or Unbalanced
6. If Object A is pushing with a force of 3 N to
the right and Object B is pushing with 3 N to the left, draw a picture of how these forces would look and the final direction of motion. = 3 -3 =
a. Net Force = 0 N
b. Balanced or Unbalanced: Balanced

8. Calculating Force Measured in Newtons (N) = kg•m/s/s
Force = Mass X Acceleration
F = m X a
Measured in Newtons (N) = kg•m/s/s
With what force will a bike hit a tree if the bike has a mass of 500kg and its accelerating at a rate of 0.5m/s/s?
Formula:
Work:
Answer: F
F = m X a M A
= 500 X .5
= 250 Kg• m/s/s or 250 N

9. Calculating Force
What is the mass of a falling rock if it hits the ground with a force of 10 N and has an acceleration of 9.8 m/s/s?
Formula:
Work:
Answer:
M = F/A
10 / 9.8
1.02 kg

10. Calculating Force
What is the acceleration of a racecar if it has a mass of 125kg and hits the wall of turn two with a force of 65N?
Formula:
Work:
Answer:
A = F/M
65/125
.52 m/s2