Question

A car sitting at a red light begins to accelerate at 2 m/s2 when the light turns green. It continues with this acceleration until it reaches a speed of 20 m/s. It then travels at this speed for another few minutes. How far does the car travel in the first 35 s after the light changes to green

Answer 1

Answer:

    x_total = 600 m

Explanation:

This is an exercise and kinematics, let's find the time it takes to reach the velocity  20 m / s

          v = v₀ + a t

           

as part of rest v₀ = 0

          t = v / a

          t = 20/2

          t = 10 s

let's find the distance traveled in this time

          x₁ = vo t + ½ a t2

          x₁ = 0 + ½ 2 10²

          x₁ = 100 m

The remaining time is

          t₂ = 35 - t

          t₂ = 35 - 10

          t₂ = 25 s

as in this range it has a constant speed

          v = x₂ / t₂

          x₂ = v t₂

          x₂ = 20  25

          x₂ = 500 m

the total distance traveled is

           x_total = x₁ + x₂

           x_total = 100 + 500

           x_total = 600 m