Question

The brakes are applied to a moving car, causing it to uniformly slow down. while slowing, it moves a distance of 40.0 m in 7.25 s to a final velocity of 1.20 m/s, at which point the brakes are released. (a) what was its initial speed (in m/s), just before the brakes were applied?

A) 8.0 m/s
B) 10.0 m/s
C) 12.0 m/s
D) 15.0 m/s

Answer 1

To find the initial speed of the car before the brakes were applied, use the equation: Initial velocity = Final velocity - (Acceleration × Time)

Step-by-step explanation:

To find the initial speed of the car before the brakes were applied, you can use the equation:

Final velocity = Initial velocity + (Acceleration × Time)

At the point when the brakes were released, the final velocity is 1.20 m/s. Given that the car moved a distance of 40.0 m in 7.25 s, we can use this information to solve for the initial velocity. Rearranging the equation, we have:

Initial velocity = Final velocity - (Acceleration × Time)

Initial velocity = 1.20 m/s - (Acceleration × 7.25 s)

Since the car is slowing down, the acceleration is negative. Therefore, the equation becomes:

Initial velocity = 1.20 m/s - (-Acceleration × 7.25 s)

Plugging in the known values, we can solve for the initial velocity.