Forces of Friction

We began by reviewing the subject matter from Friday, which concerned frictional forces...

• Static friction is defined as the friction that prevents a stationary object from beginning to move.
• Limiting static friction/Starting friction is defined as the maximum value of the force of friction that occurs just before the object starts to move.
• Therefore, if a force that is smaller than the limiting static friction is applied to a stationary object, the object won't move unless the force is increased and overcomes the limiting static friction, and once the object is in motion less force is needed to keep it in motion.
• is the formula used to determine the force of friction. As the mass increases, the Net Force increases, as well as the amount of friction.
• Without an applied force, a static frictional force does not exist.

We then did four examples that required us to utilize and manipulate the formulas concerning friction. Example one is shown below.

Ex.1) If the total weight of a skier and the skis is 500.0 N and a force of 35 N is needed to start the skier moving on the snow, determine the coefficient of static friction.

• We manipulate the formula to achieve = Ff/Fn
• = 35 N/500.0 N
• Therefore, = 0.070

Finally, we worked on practice questions from the textbook (Page 169, 1-4).

This link leads us to a video that explains the forces of friction in greater detail: http://www.youtube.com/watch?NR=1&v=cKUzHgBI_GY

Gbergz 360 is up next.