High School

7. A driver of a car travelling applies the brakes and accelerates uniformly in
the opposite direction. The car stops in 5s. Another driver going at 3km/h in
another car applies is brakes slowly and stops in10s. Which of the two cars
travelled farther after the brakes were applied?
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7 A driver of a car travelling applies the brakes and accelerates uniformly inthe opposite direction The car stops in 5s Another driver going at

Answer :

After the brakes were applied, car A traveled farther.

The distance traveled by the cars is calculated by applying the following formula as shown below.

s = t(u + v)/2

where;

  • t is the time of motion of the cars
  • u is the initial velocity of the cars
  • v is the final velocity of the cars

The final velocity of the cars when they stop = 0 m/s

For car A

u = 52 km/h = 14.44 m/s

s = 5(14.44)/2

s = 36.1 m

For car B

u = 3 km/h = 0.83 m/s

s = 10(0.83)/2

s = 4.16 m

Thus, after the brakes were applied, car A traveled farther.

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