Question

A boy drops a ball of mass 500 g from a height 10 m. Ignoring the effects of air resistance
Calculate the kinetic energy it possess at point 3 (i.e., just before it reaches the earth
(g = 10 m s-2).​

Answer 1

Answer:

(a). Mass of the Body = 500g

Height = 10 m.

Acceleration due to gravity = 10 m/s².

Using the Formula,Potential Energy = mgh

= 0.5× 10 × 10 = 50 J.

(b). Now, By the law of the conservation of the Energy, Total amount of the energy of the system remains constant.

∴ Kinetic Energy before the body reaches the ground is equal to the Potential Energy at the height of 10 m.

∴ Kinetic Energy =50 J.

(c). Kinetic Energy = 50 J.

Mass of the ball = 0.5kg.

∵ K.E. = 1/2 × mv²

∴ 50 = 1/2 × 0.5× v²

∴ v² = 100/0.5

⇒ v² = 200

∴ v = 10 √2 m/s.