Relation between power and velocity
The work done by a force for a displacement d is
Left hand side of the equation (4.40) can be written as
Substituting equation (4.41) and equation (4.42) in equation (4.40), we get
This relation is true for any arbitrary value of dt. This implies that the term within the bracket must be equal to zero, i.e.,
A vehicle of mass 1250 kg is driven with an acceleration 0.2 ms-2 along a straight level road against an external resistive force 500 N.Calculate the power delivered by the vehicle’s engine if the velocity of the vehicle is 30 m s-1 .
The vehicle’s engine has to do work against resistive force and make vechile to move with an acceleration. Therefore, power delivered by the vehicle engine is