CHAPTER 12

Forces

1 . A light string holds three identical masses over a lightweight pulley as shown in the figure. When the
masses are released, the acceleration of the masses will be
(A) 2g
(B) g
(C) 2g/3
(D) g/2
(E) g/3

2 . While removing paint, a carpenter accelerates a rough sanding block up a wall as shown. The
coefficient of friction between the block and the wall is μ. What is the net force on the sanding block?
(A) F + mg + Ff
(B) F cos θ - mg - μF sin θ