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2 votes
A steel ball of mass 5kg is dropped from a tower of height 12m. What will be the kinetic energy of ball on hitting the ground? With what velocity will the ball hit the ground?

1 Answer

5 votes
To calculate the kinetic energy of the ball when it hits the ground, we need to use the formula:

Kinetic Energy (KE) = 1/2 * mass * velocity^2

Given:
Mass of the ball (m) = 5 kg
Height of the tower (h) = 12 m

First, let's calculate the velocity of the ball when it hits the ground using the concept of gravitational potential energy:

Gravitational Potential Energy (PE) = mass * gravity * height

PE = m * g * h

Where gravity (g) is approximately 9.8 m/s^2.

PE = 5 kg * 9.8 m/s^2 * 12 m
PE = 588 J

The gravitational potential energy is converted into kinetic energy when the ball falls, so:

KE = PE = 588 J

Now we can rearrange the formula to solve for the velocity:

KE = 1/2 * m * v^2

588 J = 1/2 * 5 kg * v^2

v^2 = (588 J * 2) / 5 kg
v^2 = 2352 J / 5 kg
v^2 = 470.4 J/kg

v ≈ √470.4 J/kg
v ≈ 21.7 m/s

Therefore, the kinetic energy of the ball on hitting the ground is 588 J, and the velocity of the ball when it hits the ground is approximately 21.7 m/s.
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