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

Average acceleration of the particle during the 2.4 s interval is - 20 m/s²

Explanation:

We have equation of motion v = u + at

Initial velocity, u = 18 m/s

Final velocity, v = - 30 m/s

Time, t = 2.4 s

Substituting

v = u + at

-30 = 18 + a x 2.4

a = - 20 m/s²

Acceleration is - 20 m/s²

Average acceleration of the particle during the 2.4 s interval is - 20 m/s²