Question

An automobile of mass m accelerates from rest. If the engine supplies a constant power P, the velocity at time t is given by -
A. `(2Pt)/(M)`
B. `sqrt((2Pt)/(m))`
C. `(Pt)/(2M)`
D. `sqrt((Pt)/(2 M))`

Answer 1

Correct Answer - B
(b) We have, P=Fv=constant (given)
`rArr M((dv)/(dt))v=P" or ""vdv"=(Pdt)/(M)`
Integrating both side, we get
`(v^(2))/(2)=(P)/(M)t" or "v=sqrt((2Pt)/(M))`