

InterviewSolution
Saved Bookmarks
1. |
A bullet of mass 0.5 kg slows down from a speed of 5 m s-1 to that of 3 m s-1. Calculate the change in kinetic energy of the ball. |
Answer» Mass of ball = 0.5kg Initial velocity = 5m/s Initial kinetic energy = 1/2 × mass x (velocity)2 = 1/2 ×0.5 ×(5)2 = 1/2 ×0.5 ×25=6.25J Final velocity of the ball = 3m/s Final kinetic energy of the ball =1/2 × mass x (velocity)2 = 12 × 0.5 x (3)2 = 12 ×0.5 x 9 = 2.25J Change in the kinetic energy of the ball = 2.25 J − 6.25J = − 4J There is a decrease in the kinetic energy of the ball |
|