Question

power of car of mass 1200kg is 25kW.find the minimum time required to reach a velocity of 90km/h by the car after starting from rest .

Answer 1

P = F v
25000 = F x 25. (90kmph is 25m/s)
thus F is 1000

now F = ma
1000 = 1200 x a
thus a = 10/12

again
starts from rest so initial velocity is 0
final velocity is 25m/s

v = u + at
25 = 0 + 10/12 t
t= 30sec