Force & Friction

What is friction?

• how fast an object is moving

• a force that opposes motion between two surfaces that are touching

• a push or pull on an object

• the rate at which velocity changes

What is force?

• someone ice skating

• hills and valleys

• speed in a given direction

• a push or pull on an object in a certain direction

Tags

NGSS.3-PS2-1

What kind of friction do you experience when you are roller blading?

• rolling friction

• sliding friction

• fluid friction

• static friction

How can you increase friction?

• make the surface smoother

• use a lucbricant

• make the surface rougher

• put wheels on the object

How can you reduce friction?

• make the surface rougher

• add sand to the surface

• add weight

• use a lubricant

What is the SI unit for force?

• pounds

• newtons

• grams

• centimeters

If two people are pulling on a rope with 50 Newtons of force in opposite directions, the net force is

• 10 N

• 50 N

• 100 N

• 0 N

Tags

NGSS.MS-PS2-2

If two people are pushing on a box in the same direction, what is the net force if one person pushes with 10 N and the other with 15 N?

• 25 N

• 5 N

• 0 N

• 150 N

Tags

NGSS.MS-PS2-2

If an object is not moving (stationary), the forces are...

• balanced

• unbalanced

• non-existant

What two factors affect friction?

• height and weight of object

• size and roughness of surface

• pressure and net force

• roughness of surface and weight of objects