(a) Write the formula for acceleration. Give the meaning of each symbol which occurs in it.
(b) A train starting from railwaystation attains a speed of 21 ms in one minute. Find its acceleration.
(a) Let the initial velocity be 'u' and final velocity be 'v'.
Time taken to change the velocity from u to v = 't'
We know that acceleration means a change in velocity.
Hence, acceleration = (v−u)t
(b) Initial velocity of train = 0
Final velocity of train = 21 ms
Time taken = 1 minute = 60 sec
So, acceleration = (Change in velocity)time = (v−u)t = (21−0)60 = 2160 = 0.35 m/s2