Question

A body of mass 2 kg rests on a horizontal plane having coefficient of friction µ = 0.5. At t = 0 a horizontal force Vector F is applied that varies with time F = 2t. The time constant t₀ at which motion starts and distance moved in t = 2t₀ second will be ...... and ........ respectively.

Answer 1

Here f_max = µ mg = 0.5 × 2 × 10 = 10 N

for sliding starts,

F > µ mg

F > 10

or 2t > 10

or t > 5 

∴ t₀ = 5 second.