A force of 75 N is applied to the side of a crate resting on a level floor. The crate has a mass of 25 kg. If the coefficient of static friction is 0.15, is the 75 N force enough to make the crate accelerate? Explain why or why not.
Answer (2)
If the coefficient of static friction is 0.15, then 0.15 of the crate's weight shows up as a force resisting the horizontal pull. So we really only need to know the crate's weight.
Weight = (mass) x (gravity) = (25) x (9.8) = 245 newtons.
0.15 of 245 newtons = 36.75 newtons .
The force due to friction that's holding the crate back, not letting it start sliding, is 36.75 newtons. If you push it with 75 newtons of force, then that *** IS*** enough to make the crate accelerate.
The applied force of 75 N exceeds the maximum static friction force of approximately 36.79 N. Therefore, the crate will overcome static friction and accelerate. Thus, 75 N is sufficient to accelerate the crate.
;
