Question

1. Suppose the car accerlerated up and down the incline. How would this affect the experiemental determinations?

2. Is the assumption justified that f would be the same for both up and down casses for the same constant speed? if not, speculate as to why there is a difference.

3. Assuming that f = uN, show that the coefficient of (rolling) friciton for the car moving down the inclined plane with a constant speed is given by u = tan (deta) - (m2/ mc cos (deta)) **Use symbols not numbers**

Answer 1

Answer 2

while going up,the friction will act with gravitation force in the same direction to decelerate the machine.

while going down,the friction will act in opposite to the gravitational pull to stop the machine from free fall.

2) f will be the same as f=coefficeint of friction*normal force

now normal force=gravitational force*cos (angle with the horizontal)

as normal force does not change,f will remain the same'

3)if it is moving down with constant speed,then friction force balances the gravitational pull.

then m*g*sin theta=u*m*g*cos theta

so u=tan theta