Question

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

Answer 1

hello friend here is ur answer


given : m= 1200kg

power =25 kw

v= 90km/h = 90×5÷18= 25

since we know that

p = m×v^2÷t

p= 1200×(25)^2÷t

25kw = 1200×625/t

25×1000= 750000÷t

25÷750 = t

t = 0.03 second


hope it hepls ,

sorry for awaiting yoi

Answer 2

Hi there!


____________________________



Given :



Initial velocity (u) = 0



Final velocity (v) = 90 km/h = 25m/s.



Mass of car = 1200 kg.



Power of engine = 25 kW = 25000 W



We know that..



Power = work done / time



Work done = 1 / 2 mv²



=> 1/2 × 1200 × 25 × 25



=> 600 × 625



=> 375000 Joule.



Now,



Time = work done / power



Time = 375000 / 25000



Time = 15 secs.



Hence, the required time is 15 secs.




____________________________



Thanks for the question!



☺️☺️☺️