A block of mass is projected along a horizontal table with an initial speed of
PHYSICS · Subjective · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A block of mass 2.0kg is projected along a horizontal table with an initial speed of 6.0ms−1. The table consists of two successive rough strips, each 1.5m long. On the first strip the coefficient of kinetic friction between the block and the table is 0.30, while on the second strip it is 0.20. Neglect air resistance.
(i) Calculate the magnitude of the frictional force acting on the block in each strip.
(ii) Determine the work done by friction in each strip and hence the total work done by all forces on the block after it has travelled the entire 3.0m.
(iii) Using the work–energy theorem, find the speed of the block as it leaves the second strip.
(iv) Comment briefly on the form in which the mechanical energy lost by the block is ultimately stored.