Question

1. Two masses are connected by a string which goes over an ideal pulley. Block A gas a mass of 3kg and the rough plane is inclined 30 degrees to the horizontal. The coefficients of friction between block A and the plane are Us=0.4 and Uk=0.2. The system initially at rest. If mass B increases gradually by addjng small masses on the top, what is the minimum value of mass B needed for mass A to start moving up?

2. A 10kg crate is pulled down a rough incline with a Force of 40N parallel to the inclined surface. the inclined surface makes an angle of 20 degrees with the horizontal. The coefficient if kinetic friction is 0.3 and the crate is pulled a distance of 8m. Calculate the work done by the force, the work done by gravity on the crate, the work done by the friction on the crate, and the work done by the normal force.

Answer 1