A Block weighing 72.2 N rests on a plane inclined at 20.0 deg. to the horizontal. The coefficients of static and kinetic friction are 0.22 and 0.12 resp.

What is the minimum magnitude of F that will start the block moving up the plane? (I also got 9,74 N for this.. but wrong answer.)

As well, what is the magnitude of F required to move the black up the plane at constant velocity? (I got 16.5 N for this... but it was also the wrong answer)

help please!!!

1 answer

I assume F is up the plane, parallel to the plane.

Forces on the block, using Up the plane as positive.

F -mgsinTheta - mu*mgCosTheta=0

I don't get your answers..