Question

A body travels 200m in the first two second and 220m in the next four second. The velocity at the end of the seventh second from the start will be
1) 10 m/s
2) 15 m/s
3) 220 m/s
4) 5 m/s​

Answer 1

Explanation:

s=ut+ 1/2at^2

For case 1.

200=2u+2a

u+a=100....(1)

For case 2. .i.e. next 4 seconds, we have distance =420 cm and time =6 s

420=6u+18a

u+3a=70....(2)

Solving equation 1 and 2, we get,

u=115 cm/s and a=−15 cm/s

2

Now by

v=u+at

v=115−15×7

v=10 cm/s

Hence answer is A.

Hope you are satisfied with it