This is a force that pulls everything to the ground.
Gravity
Name the force that slows things down
Friction
When does friction happen?
Friction takes place when objects runs against each other.
Is the friction more or less when the ground is slippery?
Less Friction. Smooth surfaces has less or no bumps and they make it easier to push objects.
Is the friction more or less when you rub your book against a towel?
More friction. Because towel has a rough texture. More bumps make the object hard to move.
What happens when you kick a ball on the grass?
roll, slow down, stop. Friction between the ball and the grass slows the ball. Friction causes the ball to slow and stop. If there were no friction, the ball wo
When do you need to apply more force? Pushing a heavy box on an ice floor or grass?
Grass! Friction also makes it harder to push objects across rough surfaces. You need more force to push an object on a rough surface than on a smooth one.
Does this surface smooth or rough? Why?
Smooth! Smooth surfaces have much smaller bumps and less friction.
Does this surface look rough or smooth? Why? Friction?
Rough! It is covered with many bumps and grooves which increases friction when surfaces rub together.
Why is friction helpful?
walk, slide on a sheet of ice. brakes use friction to slow down and stop a moving car.
