Question

An engine of `100H.P` draws a train of mass `100` metic ton with a velocity of `36km h^(-1)` Find the coefficient of friction.

Answer 1

Correct Answer - `0.0076`
Here `P = 100 HP = 100 xx 746 "watt"`
`upsilon =36km h^(-1) = 10ms^(-1)`
If `F` is frictional force overcome by the engine then `P = F xx upsilon F = (P)/(upsilon) = (100 xx 746)/(10) = 7460 N`
`R = mg = 100 xx 1000 xx 9.8 N = 9.8 xx 10^(5)`
`mu = (F)/(R) = (7460)/(9.8 xx 10^(5)) = 0.0076` .