Question

Find the height from which body of a mass 50kg should fall in order to have the K.E of a car of mass 200kg travelling at 10ms^-1 Given g = 9.8ms^-2.

Answer 1

Mass of a body, m₁ = 50 kg

Mass of car m₂ = 200kg

velocity of the car v = 10ms^-1 g = 9.8ms^-2

P.E of the body, P.E = mgh

= 50 × 9.8 × h

= 490h

K.E of the car K.E = \(\frac{1}{2}\)m²v²

\(\frac{1}{2}\)× 200 × 10²

= 10,000J

But P.E of body = K.E of car

490h = 10,000

h = \(\frac{10,000}{490}\) = 20.41 m.