Question

. A man if 20 kg is dropped from a height of 5 m. Find its KE as it just reaches the
ground?
​

Answer 1

$\LARGE{ \underline{\underline{ \sf{Required \: answer:}}}}$

GiveN:

• Mass of the body = 20 kg
• Height from which it is dropped = 5 m

To FinD:

• KE of the body as it reaches the ground?

Step-by-Step Explanation:

According to law of conservation of energy, all the potential energy possessed by the body at certain height gets converted into kinetic energy when it reaches the ground. That means:

• Potential energy at a height of 5 m = Kinetic energy of the body as it reaches ground.

Finding PE at a height of 5 m

= mgh

= 20 × 9.8 × 5 J

= 100 × 9.8 J

= 980 J

We above just determined that KE at ground will be equal to the Potential energy possessed at a height of 5m.

Hence,

KE of the body when it reaches ground:

$\huge{ \boxed{ \sf{ \purple{980 \: J}}}}$

Answer 2

Answer:

${ \underline{ \sf{ \underline{☃Question:}}}}$

A mass of 20 kg is dropped from a height of 5m.Find it's K. E as it's reaches the ground

$\underline{ \sf{ \underline{☃ Given:}}}$

• Mass of object = 20kg
• Height = 5m

$\underline{ \sf{ \underline{☃Find:}}}$

• Find its KE as it just reaches the ground?

$\underline{ \sf{ \underline{☃ Solution:}}}$

↪ when the body is released from a height of 5 meters then all the kinetic energy will be equal to potential energy.

So, K•E = mgh

(Acceleration due to gravity (g) = 9.8 m/s²)

${ \to{20 \times 9.8 \times 5}}$

${ \to{980J}}$

Therefore,

KE of the body when it reaches ground is 980J