Question

A body covers 200 CM in the first 2 seconds and 220 CM in the next 4 seconds The velocity of the body at the end of the 7 second will be

Answer 1

let initial velocity = u & accleration is a then

distance travelled in 4 sec = S6

using , s=ut + at2/2

          S6 = 4u + a36/2

               =  6u+18a

distance covered in 2 sec = S2 = 2u + 4a/2

                                           =2u+2a = 200           (given)

                                       u+a = 100             ........................1

now distance covered in 2 to 6 sec is given 220cm

      S6-200 = 220

     6u + 18a = 420       

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

from 1& 2

a = -15 & u=115

velocity after 7 sec = V7

       V7 = u + at

           =115 - 15*7=10cm/sec

Answer 2

Hi mate

Kindly refer the attachment

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