001 10.0 points
this question is typical on some driver's li-
cense exams: a car moving at 49 km/h skids
13 m with locked brakes.
how far will the car skid with locked brakes
at 122.5 km/h? assume that energy loss is
due only to sliding friction.
answer in units of m.

81.25 m

Explanation:

49 Km/h is initial velocity, converted to m/s we get

From kinematics equation

where v is final velocity, u is initial velocity, a is acceleration, s is distance and making a the subject of formula, and when it skids, final velocity is zero hence substituting 0 m/s for v, 13.61 m/s for u and 13 m for s

When the initial velocity is 122.5 Km/h, converted to m/s

From kinematics equation

making s the subject of formula

Substituting 0 for v, 34.03 m/s for u, for a we obtain

need to see circuit to get time constant