The combined mass of a cyclist and the bike is 90 kg . Determine the increase in kinetic energy when the speed increases from 6.0 km/h to 12 km/h .

Step-by-step solution

Initial speed v₁ = 6.0 km/h = 6.0 5 18 m/s = 5 3 m/s Final speed v₂ = 12 km/h = 12 5 18 m/s = 10 3 m/s Initial kinetic energy K₁ = 1 2 m v₁^2 = 1 2 90 ( 5 3 )^2 = 45 25 9 = 125 J Final kinetic energy K₂ = 1 2 m v₂^2 = 1 2 90 ( 10 3 )^2 = 45 100 9 = 500 J Increase in kinetic energy K = K₂ - K₁ = 500 - 125 = 375 J