Question

You throw a ball of mass 190 g upward. When the ball is 2 m above the ground, headed upward (the initial state), its speed is 18 m/s. Later, when the ball is again 2 m above the ground, this time headed downward (the final state), its speed is 18 m/s. What is the change in the kinetic energy of the ball from initial to final state?

Answer 1

Change in Kinetic energy is zero

Step-by-step explanation:

Given

Mass of Ball
`= 190` grams
`= 0.19` Kg

Speed at height of
`2` m
`= 18 (m)/(s)`

Kinetic energy is equal to

`(1)/(2) mv^2`

Where M is the mass of the object and v is the velocity of the object

Change in kinetic energy
`= KE_2 - KE_1`

Substituting the given values we get -

Change in kinetic energy
`= (1)/(2) m_1v_1^2 - (1)/(2) m_2v_2^2`

Change in kinetic energy
`= (1)/(2) 0.19*18^2 - (1)/(2) 0.19*18^2\\= 30.78 - 30.78\\= 0`

Hence, the change in Kinetic energy is zero