Question

A long plank of mass m is intially at rest on a frictionless surface .A small block with mass m(m=alpham) anf intial speed u0nsludes on the top of the larger plank. The coefficient of friction between the block and plank is u

Answer 1

Answer:

The answer will be - umgL

Explanation:

According to the problem it is given that the mass of the plank is m and the mas of the block is alpham , the initial speed of the block is u0

Now let the friction force needed to move for the block is f

let the displacement is L

Now as f is constant therefore the workdone ,dw = f.ds => dw = f ds cos180

dw = - fds

Now by integrating

w = -f L

   = -umgL