12 13 Two ice skaters are gliding across the horizontal ice surface at an ice rink. (Source: © ITAR-TASS News Agency/Alamy Stock Photo) (a) Initially the skaters move together with a speed of 5.6 m s–1. The male skater pushes the female skater forwards. After being pushed, she has a forward speed of 7.5 m s−1. Calculate the speed of the male skater immediately after pushing the female skater forwards. mass of male skater = 66 kg mass of female skater = 52 kg (3) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. Speed of male skater = ...................................................... Turn over 13 (b) Explain why the male skater experiences a change in his velocity when he pushes the female skater forwards. You should make reference to Newton’s laws of motion in your explanation. 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(c) When the male skater pushes the female skater forwards, the total kinetic energy of the skaters increases. Explain why kinetic energy is not conserved in this interaction. 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(Total for Question 13 = 9 marks)