A block rests on a rough incline

PHYSICS · Single correct · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics

Problem

5\,\text{kg}

block rests on a rough

30^{\circ}

incline. The coefficients of static and kinetic friction between the block and the plane are

\mu_{s}=0.40

and

\mu_{k}=0.30

respectively. The block is connected by a light string over a frictionless pulley to a hanging mass

m

. The minimum value of

m

(in kg) that will just start pulling the block up the plane is closest to (take

g = 10\,\text{m s}^{-2}

\sin 30^{\circ}=0.5

\cos 30^{\circ}=0.866

) (a)

6.1

(b)

3.8

(c)

4.2

(d)

2.5