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Home » A ball of mass 0.5 kg slows down from a speed of 5m/s-1 to that of 3m/s-1. Calculate the change in kinetic energy of the ball.
A ball of mass 0.5 kg slows down from a speed of 5m/s-1 to that of 3m/s-1. Calculate the change in kinetic energy of the ball.
Class 10 | ICSE | Physics | Selina | Work Energy
A ball of mass 0.5 kg slows down from a speed of 5m/s-1 to that of 3m/s-1. Calculate the change in kinetic energy of the ball.

Solutions:

According to the questions –

Mass of ball is  0.5 kg

Initial velocity is  5 m / s

Using the expression of the kinetic energy, we have –

Initial kinetic energy = 1 / 2 × mass × (velocity)2

= 1 / 2 × 0.5 × (5)2 = 1 / 2 × 0.5 × 25

Initial kinetic energy  = 6.25 J

Final velocity of the ball is  3 m / s

Again, Using the expression of the kinetic energy, we have –

Final kinetic energy of the ball = 1 / 2 × mass × (velocity)2

= 1 / 2 × 0.5 × (3)2 = 1 / 2 × 0.5 × 9

= 2.25J

So, the change in the kinetic energy of the ball is given as follows

 = 2.25 J – 6.25 J = – 4J

Therefore, there is a decrease in the kinetic energy of the ball.

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