Question

A car is travelling at 14 m/s when the traffic light ahead turns red. The car brakes and comesto a stop in 5.0 s. Calculate the acceleration of the car.

Answer 1

The car decelerates at a rate of -2.8 m/s² to come to a stop from an initial speed of 14 m/s over a period of 5 seconds.

Step-by-step explanation:

To calculate the acceleration of the car, we can use the formula for acceleration a = (vf - vi) / t, where vf is the final velocity, vi is the initial velocity, and t is the time. The car's initial velocity vi is 14 m/s and it comes to a stop, so the final velocity vf is 0 m/s. The car takes 5.0 seconds to stop after the light turns red.

Substituting these values into the formula, we get:

a = (0 m/s - 14 m/s) / 5.0 s

a = -14 m/s / 5.0 s

a = -2.8 m/s2

The negative sign indicates that the car is decelerating.

Answer 2

The acceleration of the car is -2.8 m/s². The negative sign indicates that the car is decelerating or slowing down.

To calculate the acceleration of the car, you can use the following formula:

Acceleration (a) = Change in Velocity (Δv) / Time (t)

Step 1: Determine the initial velocity (u), final velocity (v), and time (t).

- The initial velocity (u) of the car is 14 m/s.

- The final velocity (v) is 0 m/s because the car comes to a stop.

- The time (t) it takes to come to a stop is 5.0 s.

Step 2: Calculate the change in velocity (Δv).

Δv = v - u

Δv = 0 m/s - 14 m/s

Δv = -14 m/s

Step 3: Calculate the acceleration (a) using the formula:

a = Δv / t

a = (-14 m/s) / (5.0 s)

Step 4: Calculate the acceleration:

a = -2.8 m/s²

So, the acceleration of the car is -2.8 m/s². The negative sign indicates that the car is decelerating or slowing down.