posted by Nancy .
An object slides down a inclined surface in the presence of kinetic friction forces.
At the given inclination the kinetic friction force is found to be of magnitude 90 N.
Now, the angle that the surface makes with respect to the horizontal is increased and the object continues to slide down the surface.
The magnitude of the new kinetic friction force present will be ... ?
I think that it should be smaller than 90N because if you think about it logically an increased angle would make the slope steeper, and things fall faster down steeper slopes which means that the friction force decreases; however i know that this is not really a valid explanation.
Could someone five a better explanation?
IF the angle is increased, the normal component of weight decreases, thus friction is less. Fricion= mg*mu*cosTheta.
If Theta increases, cosTheta decreases