A driver of a car slows to a stop. The decrease in speed is constant. When the driver first applies the brakes, the car is going 50mi/h. After 5 s the car is traveling 30mi/h. About how long does it take the car to stop?

Question

A driver of a car slows to a stop.  The decrease in speed is constant.  When the driver first applies the brakes, the car is going 50mi/h.  After 5 s the car is traveling 30mi/h.  About how long does it take the car to stop?

openstudy4life · Answer

Okay,it takes the car 5 seconds to go down 20 mph, so it will take 2.5 seconds to go down 10 mph. So after the car goes down to 30 , it will take 7.5 seconds to stop. The total decrease is 12.5 seconds for the car to go down completely. 


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