# physics

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disregard the previous I did not include the first part
This question is typical on some driver's license exams: A car moving at 50 km skids 15 m with locked brakes.How far will the car skid with locked brakes at 120 km/h?

• physics -

work done by friction = F d
F is friction force, assume the same in both cases

F d = (1/2) m v^2

F(15) = (1/2) m (50)^2
F d = (1/2) m (120)^2

d=(1/2) m (120)^2 (15)/ [(1/2)m (50)^2 ]

d = 15 (120)^2/(50)^2

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