Question

A body travels 200 cm in the first 2s and 220 cm in the next 5s.Calculate the velocity at the end of the seventh second from the start.

Answer 1

Formula :
s = ut + 1/2 at^2

Case 1:-
Displacement is covered in 2s
200 = u * 2 + 1/2 * a * 2^2
200 = 2u + 2a

Case 2 :-
220 = u * 5 + 1/2 * a * 5^2
220 = 5u + 25/2 a

The distance covered between 2 - 5 seconds.
220 - 200 = ( 5u + 25/2a ) - ( 2u + 2a )
20 =  5u - 2u + 25/2a - 4/2a
20 = 3u + 21/2a