A train of weight \(10^7\ N\) is running on a level track with uniform speed of \({36\, km\, h^{-1}}\). The frictional force is 0.5 kg f per quintal. If \(g ={ 10 \, m \, s^{-2}}\), power of engine is
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)): 
Read More: Work and Energy