Question

If the energy of a ball falling from a height of 10 metres is reduced by 40%, how high will it rebound?(Ans : 6 m). Solve the example.

Answer 1

Answer:

6m

Explanation:

If the energy of a ball falling from a height of 10 metres is reduced by 40%, then it will rebound by 6 m

we know that

Potential Energy of the ball  = mgh

= mg * 10

= 10 mg

Energy reduced by 40 %

= (40/100)10mg = 4 mg

Remaining energy = Energy at beginning - reduced energy

remaining energy = 10 mg - 4mg = 6mg

potential energy it will possess now  will be equal to reaming energy so

6mg = mgH

=> H = 6

Height = 6 m

Answer 2

Answer:

The answer is 6 metres.

Explanation:

According to the question if the energy of a ball falling from a height of 10 metres is reduced by 40%, then it will rebound by 6 m

The question is solved like this:

Potential Energy of the ball  = mgh

= mg * 10 = 10 mg

Energy is reduced by 40 %

= (40÷100) × 10 mg = 4 mg

The formula is:

Remaining energy= Energy at beginning - reduced energy

Remaining energy =            10 mg             -             4 mg          = 6 mg

The potential energy it will now possess will be equal to remaining energy so

6mg = mgH

H = 6

Height = 6 m