We started off class with a friday quiz on Newton's laws of motion, and then did some examples on the board.
After that we started talking about frictional forces. There are three kinds of frictional forces.
1) Static Friction - the friction that tends to prevent a stationary object from starting to move.
2)Limiting Friction - the maximum value of the force of friction which occurs just before the object starts to move. (starting friction)
3)Kinetic Friction: the force of friction that opposes the motion of a moving object. It is always less than the limiting static friction. (means that once the object starts moving the force of friction drops)
We then talked about the formula for the force of fricion $Ff=uFn$
u= Coefficient of friction (no unit)
Fn= Normal force (N)
Ff= Force of fricion
We finished the day talking about a problem with bricks and how the frictional force of a brick on its end is the same as a brick on its side.
Jolene is next.
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