A loaded penguin sled weighing rests on a plane inclined at angle to the horizontal. Between the sled and the plane, the coefficient of static friction is , and the coefficient of kinetic friction is .

(a)What is the least magnitude of the force , parallel to the plane, that will prevent the sled from slippig down the plane?

(b)What is the minimum magnitude that will start the sled moving up the plane?

(c)What value of is required to move the sled up the plane at constant velocity?

Thankyou... I'm having a hard time grasping the concept of static & kinetic friction.