Block of mass rests on a horizontal surface

PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion

Problem

Block

A

of mass

m_1 = 4.0\,\text{kg}

rests on a horizontal surface. A light, inextensible cord runs from block

A

over a frictionless pulley at the edge of the table to a hanging block

B

of mass

m_2

. The coefficient of kinetic friction between block

A

and the table is

\mu_k = 0.25

, and the coefficient of static friction is

\mu_s = 0.30

. The cord and pulley are aligned so that all motion, if any, is purely along the direction of the cord. (a) Assuming the blocks are already in motion, determine the value of

m_2

that results in zero acceleration of the two-block system. (b) If the system is initially at rest, find the range of values of

m_2

for which the blocks will remain at rest. (c) Describe qualitatively how increasing the coefficient of kinetic friction to

0.40

would affect the value of

m_2

found in part (a), and justify your answer in terms of the forces acting on block

A

. No numerical calculation is required.

Related theory

Browse the problem library