Question

a bus and a car have same kinetic energy which of it is moving fast? explain.

Answer 1

Let mass of car = 50 kg

Mass of buss = 150 kg

Velocity of car = 70 ms-1

Velocity of bus = x

(Kinetic energy = 1/2mv2)

so Ke of car = 1/2*50*70*70 = 122500 J

Ke of bus = 1/2*150*x2 = 75x2 J

But Ke of bus = Ke of car , so ,

122500 = 75 x2

1633.3 = x2

x=40 ms-1

So , it is clear that Velocity of car is greater than velocity of bus , because mass of car less than mass of bus.