A car weighing 500 kg working against a resistance of 500 N accelerates from rest to 20 m s. in 10 s. The work done by the engine will be (Take g = 10 m s^(-2))

A car weighing 500 kg working against a resistance of 500 N accelerate

1.	A car weighing 500 kg working against a resistance of 500 N accelerates from rest to 20 m s. in 10 s. The work done by the engine will be (Take g = 10 m s^(-2))
Answer» `1.05 XX 10^(5)J` `1.0 xx 10^5 J` `1.5 J` `1.5 xx 10^(5)J` Solution :As `V = u + at :. 20 + 0 + a xx 10` or `a = 2 ms^(-2)` Force exerted by the engine, `F = ma + f = 500 xx 2 + 500 = 1.5 xx 10^(3) N` `s = ut + 1/2 at^2 = 0 + 1/2 xx 2(10)^(2) = 10^(2)` `W = Fs = 1.5 xx 10^(5) J`