A train weighing `1000` quintals is running on a level road with a unifrom speed of `72km//h` If the frictional resistance amounts to 50g wt. per quintal find power in watt, take `g = 9.8ms^(2)`.

Answer

`9800 watt`

Explanation

Here, `m = 1000` quintals
`upsilon = 72 km h^(-1) = (72 xx 1000)/(60 xx 60) m s^(-1) = 20 m s^(-1)`
Total frictional resistance `F = 50 xx 1000 g wt`
`=5000 g wt. = 50 kg wt. =50 xx 9.8 N`
As power `=F xx upsilon`
`P = 50 xx 9.8 xx 20 = 9800 "watt"` .