Question

A car accelerates steadily so that it goes from a velocity of 20 m/s to a velocity of 40 m/s in 4 seconds. What is its acceleration?

• A. 0.2 $m/s^2$
• B. 4 $m/s^2$
• C. 5 $m/s^2$
• D. 10 $m/s^2$
• E. 80 $m/s^2$

Answer 1

Answer: (C)

5 $m/s^2$

Given,

$u=20m/sv=40m/st=4sec$

Acceleration is a measure of the change in velocity over time.

Change in velocity is $\Delta v=v-u$

$\Delta v=40m/s-20m/s=20m/s$

Since this change in velocity takes place over 4 seconds,

Car acceleration is $a=\frac{\Delta v}{\Delta t}$

$a=\frac{20m/s}{4s}=5m/s^2$