What is the accleration of the block and trolly system as the fig., if the coefficient of kinetic friction between the trolly and the surface is 0.04 ? Also Calculate friction in the string. Take `g=10"m/s"^2,` mass of the string is negligible.

Explanation

Free body diagram of the block
30-T=3a ........(i)

Free body diagram of the trolley

Where `f_(k)=mu_(k) N=0.04 xx 20 xx 10=8N`
Solving (i) & (ii), `a=0.96 m//s^(2) and T=27.2N`