Question

The coefficient of static and kinetic friction between the two blocks and also between the lower block and the ground are µ_s = 0.6 and µ_k = 0.4.

Find the value of tenstion ‘T’ applied on the lower block at which the upper block begins to slip relative to lower block.

Answer 1

The maximum static friction on upper block and lower block is

f_1max = µ_Sm₁ g

= 0.6 × 2 × 10 = 12 N

The maximum static friction between ground and lower block is

F_2max = µ_S (m₁ + m₂ )g

= 0.6 × 4 × 10 = 24 N

Assume that both blocks move together.

T – µ_k (m₁ + m₂ )g = (m₁ + m₂ )a

T – 0.4 × 4 × 10 = 4a

or T – 16 = 4a ...(1)

For upper block :

For just sliding,