Question

If a car slows from 27 m/s to 15 m/s in a period of 4 seconds, what was the average acceleration? Round your answer to the nearest one.

a) 3 m/s²
b) 3.75 m/s²
c) 4.5 m/s²
d) 6 m/s²

Answer 1

The average acceleration of a car slowing down from 27 m/s to 15 m/s in 4 seconds is 3 m/s².

Step-by-step explanation:

To calculate the average acceleration of a car that slows from 27 m/s to 15 m/s in a period of 4 seconds, we can use the formula for average acceleration, which is the change in velocity (∆v) divided by the time interval (∆t).

Using the given values:

• Initial velocity (vi) = 27 m/s
• Final velocity (vf) = 15 m/s
• Time interval (∆t) = 4 s

We calculate the change in velocity (∆v) as:

∆v = vf - vi = 15 m/s - 27 m/s = -12 m/s

The negative sign indicates a slowdown. Now, we calculate the average acceleration (a) as:

a = ∆v / ∆t = -12 m/s / 4 s = -3 m/s2

Note that the negative sign indicates deceleration or slowing down. Since the question asks for the magnitude of acceleration and offers positive options, we omit the negative sign and round the answer to the nearest one, which is 3 m/s2.