The power of engine of a car of mass 1200 kg is
25 kW. The minimum time required to reach a velocity
of 90 km/h by the car after starting from rest is
(1) 15 s (2) 25 s
(3) 60 s (4) 12 s
explain brief
25 kW. The minimum time required to reach a velocity
of 90 km/h by the car after starting from rest is
(1) 15 s (2) 25 s
(3) 60 s (4) 12 s
explain brief
Add an Answer
More Questions From This User See All
Answers & Comments
Verified answer
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!
☺️☺️☺️
Verified answer
Hi there!
____________________
Given :
Mass of the car = 1200 kg.
Power of the engine = 25 kW
Power of the engine = 25000 W
Initial velocity (u) = 0
Final velocity (v) = 90 km/ h
=> 90 × 5 / 18
=> 25 m/s.
Now,
Work done = 1 / 2 × m v²
Work done = 1 / 2 × 1200 × 25 × 25
Work done = 375000 Joule.
We know that,
Power = work done / time.
Time = work done / power.
Time = 375000 / 25000
Time = 15 seconds.
Hence,
The required time = 15 secs.
___________________________
Thanks for the question !
☺️☺️☺️