A block of mass 10 kg is moving in x-direction with a constant speed of 10 ms^(-1). It is subjected to a retarding force F = - 0.1x J m^(-1) during its travel from x = 20 m to x = 30 m. Its final kinetic energy will be

A block of mass 10 kg is moving in x-direction with a constant speed o

1.	A block of mass 10 kg is moving in x-direction with a constant speed of 10 ms^(-1). It is subjected to a retarding force F = - 0.1x J m^(-1) during its travel from x = 20 m to x = 30 m. Its final kinetic energy will be
Answer» 475 J 450 J 275 J 250 J Solution :According to work energy THEOREM , `K_f - K_i = W ` `:. K_f - 1/2 xx 10 xx 10^(2) = INT F dx or K_f - 500 = int_(20)^(30) - 0.1 x dx` or `K_f - 500 = -0.1 [(x^2)/(2)]_(20)^(30) = - 0.1 [(900 - 400)/(2)] = -25` or `K_f = 500 - 25 = 475 J`.