1.If a block weighs 30 pounds and has a static friction of .7 and a sliding friction of .55 and Fn=Fw

Question

a. How much force must be applied to just cause motion?
b. Once motion has begun what force must be maintained to cause constant velocity motion?

2.A plank is tilted slowly to an angle of 30 degrees with a 12 pound block on it
Find FN, FF and the static friction?

3.A force of 26lbs. causes impending motion. If the force is maintained at 26lbs.Fn=Fw=65lbs and the sliding friction is .28.
find:
a.mass of the block
b.FF
c.acceleration
What force must be maintained to cause an acceleration of 2ft/s^2?

Answer 1

1. (a) (weight)x (static friction coefficient)
(b) (weight) x (kinetic friction coefficient)

I will he glad to critique your work on the other two questions. You will usually get quicker responses here by posting one question at a time.