Unit 4 Motion Forces 1 3 Balanced and

Unit 4 Motion & Forces 1

3. Balanced and Unbalanced Forces 2

Suppose you are asked to move a heavy desk in your classroom. How would you move it? 3

You might get on one side of the desk and start pushing Or you might grab the legs and start pulling 4

Either way, you would be using a force Vocabulary: force any push or pull 5

The force you use in pushing or pulling the desk has a size F = 1200 N F = 50 N F = 600 N F = 50 N You could use a small amount of force or a lot of force Forces differ in size 6

Another way forces differ is in direction A force can be left or right, Up or down 7

The desk will not move by itself Force A force is needed to put the desk in motion 8

But even when the desk is not moving Forces are acting upon it 9

The floor is actually pushing up on the desk Floor 10

At the same time Gravity Floor The force of gravity is pulling down on it 11

If the object is not in motion The upward force is the same as the downward pull 12

The size of the forces is the same But the directions of the forces are different 13

Whenever forces are the same in size but opposite in direction They are balanced forces 14

An object that is not in motion will never move if balanced forces act on it 15

How can you move the object? You can move it because you unbalance the forces 16

The size of your force is greater than the force of air pushing on the other side of the teeter totter 17

Unbalanced forces act in opposite directions but differ in size 18

If unbalanced forces act on an object The object will always move in the direction of the greater force 19

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