A metal ball of mass 2 kg is allowed to fall freely from rest from a height of 5 m above the ground.

(a) Taking g=10 m $s^{- 2}$ ,calculate:

(i) the potential energy possessed by the ball when it is initially at rest.

(ii) the kinetic energy of the ball just before it hits the ground?

(b) What happens to the mechanical energy after the ball hits the ground and comes to rest?

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Solution

a)
1i)P.E = mgh =5 $\times$ 2 $\times$ 10 = 100J

ii) K.E = P.E = 100 J

b)Mechanical energy converts into heat and sound energy

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Similar questions

Q. A metal ball of mass

2 k g

is allowed to fall freely from rest from a height of

5 m

above the ground (Take

g = 10 m s^{- 2}

). What is the kinetic energy of the ball just before it hits the ground?

Q. A metal ball of mass

2 k g

is allowed to fall freely from rest from a height of

5 m

above the ground (Take

g = 10 m s^{- 2}

). After the ball hits the ground and comes to rest, mechanical energy is converted to:

Q. A metal ball of mass

2 k g

is allowed to fall freely from rest from a height of

5 m

above the ground (Take

g = 10 m s^{- 2}

). Calculate the potential energy possessed by the ball when initially at rest.

We know that If a ball of mass $1 k g$ is kept at a height $10 m$ possess potential energy $m g h$ i.e. $(1 \times 10 \times 10) = 100$ J. (Taking earth surface as reference, where m = mass of object, g = acceleration due to gravity, h = height of object from earth surface.) what will be the kinetic energy of the ball when the ball is allowed to freely fall from a height $10 m$ just before it hits the ground? (take g = 10 $m / s^{2}$ and neglect air drag)

Q. A ball falls to the ground as shown below:

(a) What is the kinetic energy of ball when it hits the ground?
(b) What is the potential energy of ball at B?
(c) Which law you have made use of in answering this question?

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a) 1i)P.E = mgh =5× 2 × 10 = 100J ii) K.E = P.E = 100 J b)Mechanical energy converts into heat and sound energy

a)
1i)P.E = mgh =5 $\times$ 2 $\times$ 10 = 100J

ii) K.E = P.E = 100 J

b)Mechanical energy converts into heat and sound energy