The Coefficients of Friction for Plastic on Wood Are ?_s

Multiple Choice

The coefficients of friction for plastic on wood are ?_s = 0.50 and ?_k = 0.40. How much horizontal force would you need to apply to a 3.0-lb plastic calculator to start it moving from rest?

A) 1.2 N
B) 2.7 N
C) 0.50 N
D) 0.15 N
E) 6.7 N