Question

At a certain time a particle has a speed of $18\, m/s$ in positive x-direction and $2.4\, s$ later its speed was $30\, m/s$ in the opposite direction. What is the magnitude of the average acceleration of the particle during the $2.4\, s$ interval?

• A. $20\,m/s^{2}$
• B. $10\,m/s^{2}$
• C. $5\,m/s^{2}$
• D. $2.5\,m/s^{2}$

Answer 1

Answer: (A)

$20\,m/s^{2}$

Answer 2

Average acceleration $=\frac{\text { change in veloclty }}{\text { Time taken }}$
$=\frac{-30\, m / s -18\, m / s }{2.4}=20\, m / s ^{2}$