The uniform rectangular block is released from rest with θ essentially zero and pivots in the vertical plane about the center A of its lower face on the fixed corner. (a) If the block is observed to slip when θ = 41°, find the coefficient of static friction between the block and the corner. (b) If the bottom face of the block is notched so that it cannot slip, find the angle θ at which contact between the block and the corner ceases.

Anonzero net force acts on a particle and does work. which one of the following statements is true? the kinetic energy of the particle changes, but the speed of the particle does not change. the kinetic energy of the particle does not change, but the speed of the particle does change. the kinetic energy of the particle changes, but the velocity of the particle does not change. the kinetic energy and the speed of the particle change, but the velocity of the particle does not change. the kinetic energy, speed, and velocity of the particle change.