Safe DrivingQuestion 31 of 120
If you double your speed from 20 mph to 40 mph, what happens to your braking distance?
a.It stays about the same
b.It roughly doubles
c.It becomes about four times longer
d.It becomes about ten times longer
Explanation
Braking distance increases with the square of speed, so doubling speed multiplies braking distance by about four. Assuming it stays the same or merely doubles badly underestimates the energy the brakes must absorb, and ten times overstates it.
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