Question

A driver traveling at 25 m/s to the south sees a red traffic light ahead and applies the brakes, causing the car to slow down with an acceleration rate of 4.5 m/s2. What is the direction of the car’s acceleration, north or south? How much time will it take for the car to come to a complete stop?

Answer 1

The car's acceleration is towards the north and it will take approximately 5.56 seconds for the car to come to a complete stop.

Step-by-step explanation:

The direction of the car’s acceleration when it slows down is opposite to the direction of its velocity. Since the car is moving south and slowing down, the acceleration is towards the north, which means the car experiences a deceleration or negative acceleration.

Now, to calculate how much time it will take for the car to come to a complete stop, we can use the formula a = Δv / Δt, where a is the acceleration, Δv is the change in velocity, and Δt is the change in time. Here, the final velocity will be 0 m/s since the car stops, and the initial velocity is 25 m/s south. Plugging the values in, we have -4.5 m/s² = (0 m/s - 25 m/s) / Δt, solving for Δt gives us Δt = 25 m/s / 4.5 m/s², which is approximately 5.56 seconds.

Therefore, the direction of the car’s acceleration is north, and it will take approximately 5.56 seconds for the car to stop.