How far will the car skid with locked brakes at 132 km/h? Assume that energy loss is due only to sliding friction.?

Question

This question is typical on some driver’s license exams: A car moving at 44 km/h skids

16 m with locked brakes.

How far will the car skid with locked brakes

at 132 km/h? Assume that energy loss is due

only to sliding friction.

Answer in units of m

Answer 1

To many variables. What are the conditions of the roads, weather and tire tread wear?

Answer 2

d' = d*(V'/V)^2 = 16*(132/44)^2 = 16*3^2 = 144 m

Answer 3

KE is proportional to the speed squared.

(132 / 44 )^2 * 16 m 

Answer 4

That would be a direct relationship, or 132/44 times farther.  That would be at least 3 times farther, or 48m.

That is within the expected length from the many stopping tests I have seen of new vehicles with ABS.  At 60 mph or 100 km/h, distances were about 110 feet or 34m.  Might have been shorter or longer with locked brakes.