Question

If the energy of ball falling from a height of 10 meters is reduced by 40% ,how high will it rebond?​

Answer 1

6m

Step-by-step explanation:

We know that Gravitational Potential Energy (GPE) = mgh

ATQ,

If 40% of the total energy is turned into other forms, then (100-40)% i.e. 60% will remain as GPE.

Rebound height = x% of original height

Here, Original height = 10 m

Rebound height = 60% of 10 = 60/100*10m = 6m

So, it will rebound to 6m.

Answer 2

Given

height = 10 m

Let the mass of the ball be 2 kgs .

To find

height on rebounding

Solution

first let us find the energy of ball before it bounced.

P.E.=mgh

P.E.=2*9.8*10

P.E.=196J

The energy of the ball is reduced by 40% thus, it still has 60% of its initial energy let us find this 60% of energy

P.E.=196*60/100

P.E.=117.6J

Now let us find the final height

P.E.=mgh

117.6=2*9.8*h

117.6=19.6*h

h=117.6/19.6

h=6m

Therefore the ball will rebound 6m high.