did the car hit the skunk? what was the cars displacement?

Question

A man is traveling at +96.5km/h when he sees a skunk laying on the road. It takes him 1.25 seconds after seeing the skunk to move his foot from the gas pedal to the brake pedal (during that time he keeps moving at a constant velocity). When he hits the brakes, the car accelerates at -6.49m/s squared until it comes to a stop. How far does the car travel from the time he sees the skunk until he stops? If the skunk is +75m away when he first saw it, will the car hit it?

Answer 1

Convert 96.5 km/hour = 26.81 m/s.

In 1.25 seconds, the car travels 26.81 m/s x 1.25 s = 33.51 m

 

vi = 26.81      vf = 0 (stop)      a = - 6.49 m/s2       d = ?

 

Equation of motion  vf^2 = vi ^2 + 2ad

d = (vf^2 - vi ^2)/2a  = 26.81 ^2 /(2 x 6.49) = 55.38 m

 

Total distance traveled = 33.51 + 55.38 = 89 m   >  75 m      The car hits the skunk.

 

 

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