An object starting from rest travels 20 m in first 2 s and 160 m in next 4 s. What will be the velocity after 7 s from the start?
Let acceleration (a) of the body be ‘a’.
So, to find the acceleration of the body
S = ut +
at2 ..............(i)
Where u = 0, t = 2s and s = 20m
So, by putting the values in equation (i), we get,
S =u t +
at2
20 = 0 +
x a x(2)2
20 = 
x 4a
4 a = 20x2
a = 40/4
a = 10m/s
To find final velocity (v), we use
V= u + at
V=0 + 10x7
V = 70 m/s
20