blog 4: friction

Friction is a factor in almost everything we do, even simple things like moving my calculator.  If was fairly easy to move my calculator, so that means that it has a small friction coefficient and a small normal force because friction=(friction coefficient)(normal force).  To move the calculator my push force had to be greater than the maximum static friction.  Moving the calculator from a rest position took the most push force.  After I overcame the maximum static friction the calculator moved and it took less force to keep it moving.  Once the calculator was moving, my push force had to be greater than the kinetic friction.  The kinetic friction of any object is always less than the maximum static friction.  Friction is fun!

inertia

We went to my friends house to play ping pong and eat food.  While we were playing ping pong we could rely on inertia to keep our food, bowls, cups, and ping pong paddles at rest.  Newton's first law says that if an object is at rest, it wants to stay at rest and if an object is moving, it wants to keep moving.  The food, bowls, cups, and ping pong paddles were at rest and stayed at rest.  The objects are applying a force on the ground, but its normal force balances out the force that is applied back towards the objects.