Question

A train having `60` wawgons each weight `25` tonner moving with a speed of `72 km//h`. If the force `10 N` per tonne , the power development is:
A. `3 xx 10^(5) W`
B. `3 xx 10^(6) W`
C. `3 xx 10^(7) W`
D. `3 xx 10^(4) W`

Answer 1

Correct Answer - A
Net frictional force `f = 10 xx 60 xx 25 = 15,000N`
Power `= f xx v = 15,000 xx 20 = 3 xx 10^(5) W`