# FRICTION!.

## Presentation on theme: "FRICTION!."— Presentation transcript:

FRICTION!

Friction – force that opposes (slows) motion
Vector Quantity Types of Friction – Rolling, Sliding and Fluid Frictional Force Depends on – Normal Force of object (Weight) Type of surface

Static Friction – Opposes the START of motion (when object is at rest)
Kinetic Friction – Objects in contact that are moving past each other. Kinetic Friction < Static Friction

Frictional forces are PARALLEL to surfaces
In order to get an object moving or keep it moving, it must overcome the frictional force. Fapplied = 14.8 N Ffs = 14.8 N 20 N Steel Box

**If Frictional Force = Applied Force
then the object is at rest or moving at constant velocity** **If Applied Force > Frictional Force then the object is accelerating in the direction of the applied force.**

Force of Friction

Problem A force of 10 Newtons towards the right is exerted on a wooden crate initially moving to the right on a horizontal wooden floor. The crate weighs 25 Newton’s. Calculate the magnitude of the force of friction between the crate and the floor. What is the net force acting on the crate? Is the crate accelerating?