a car is driving down the road at 20.0 m/s when the driver sees a stop sign 15.0 m ahead. the car slows down at a uniform rate and stops exactly at the stop sign. a) what is the car's acceleration? b) how much time does is take the car to stop? remember to draw a picture of the situation.



Answer :

(a) The acceleration of the car beforeit comes to stop is 40/3 m/s² or 13.33 m/s² (b) The time it takes the car to stop is 1.5 s

What is acceleration?

This can be defined as the rate of change of velocity.

(a) To calculate the acceleration of the car, we use the formula below.

Fromula:

  • v² = u²+2as......... Equation 1

Where:

  • v = Final velocity = 0 m/s
  • u = Initial velocity = 20 m/s
  • s = Distance = 15 m
  • a = Acceleration = ?

Substitute into equation 1 and solve for a

  • 0² = 20²+2×15×a
  • 0-400 = 30a
  • 30a = -400
  • a = -400.30
  • a = -40/3 or -13.33 m/s²

(b) To calculate the time it takes the car to stop, we use the formula below.

  • t = (v-u)/a
  • t = (0-20)/(-40/3)
  • t = 1.5 s

Hence, the acceleration of the car is -40/3 m/s² and the time it takes the car to stop is 1.5 s

Learn more about acceleration here:  https://brainly.com/question/605631

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