1. Welcome to Balanced and Unbalanced Forces
3-PS2-1
Welcome to Balanced and Unbalanced Forces
Provide evidence of the effects of balanced and unbalanced forces

2. Balanced and Unbalanced Forces
Tug of War!

3. How do you know this? Forces Question!
1. Two dogs were trying to pull a chew toy in opposite directions. The
toy didn’t move at all. What kind of force was the toy experiencing?
Pushing
Unbalanced
Balanced
Pulling
How do you know this?

4. Tell us why you think this way.
Aircart Challenge Questions! 20 20
_ __ cm.
____ cm.
2 ½ seconds
1 second
It took the cart 2 ½ seconds to
go through the first striped space.
It took the cart 1 second to
go through the second striped space.
2. The fact that the cart took more time to pass through the first area than the second area meant the speed
of the cart was ________________________.
a. increasing (going faster)
b. decreasing (going slower)
This must mean that the forces acting on the aircart were ____________.
a. Balanced or the same
b. Unbalanced or not the same
c. Balanced or not equal
d. Unbalanced or equal
Tell us why you think this way.
How do you know this?

5. Aircart Challenge Questions!20 20
_ __ cm.
____ cm.
2 ½ seconds
1 second
It took the cart 2 ½ seconds to
go through the first striped space.
It took the cart 1 second to
go through the second striped space.
3. What forces could cause the aircart to experience unbalanced forces?
a. Both fans running at same strength in opposite directions.
b. One fan running and the track tipped so the force of gravity was equal force.
c. One fan running and one fan off
d. Both fans off on a flat track
Balanced force
no change in speed
Balanced force
no change in speed
Balanced force
no change in speed
Now for the one that caused unbalanced forces.
Let’s go over why some of the answers won’t
give us unbalanced forces.
Unbalanced force
causes a change in speed

6. Balanced and Unbalanced Forces
Oh…… It’s on!