Kinetic energy, ke
3 marks · NormalA tennis ball of mass 0.060 kg is thrown horizontally at a speed of 18 m/s.
(a)[3 marks]
Calculate the kinetic energy of the ball.
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9.72 J (±0.1)
Also accept: 9.7 J; 9.72 Joules
Common mistakes: Forgetting to square the speed; Incorrect order of operations
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Marking points
M1 (a) · 1 mark · Substitution of values into KE = 1/2 mv^2
M2 (a) · 1 mark · Correct calculation of v^2 (18^2 = 324)
A1 (a) · 1 mark · Final answer correct with unit (9.72 J)
Worked solution
KE = 1/2 m v^2