Question

A body travels 200cm in the first two seconds
and 220cm in the next 4 seconds with
deceleration. The velocity of the body at the end
of the 7th second is​

Answer 1

Answer:

10 cm/s

Step by step Explanation:

we are assuming that the body is under uniform acceleration here. Then, the total distance travelled after the first seconds is given by

d= ut + 1/2 at power 2

where u is the initial velocity and a is the acceleration. We put the values of these quantities for the first 2 seconds:

200=2u+2a

where u is in cm/s and a is in cm/s/s

Then, at the end of 6 seconds, the total distance travelled is 220+200=420cm.

So,

420=6u+18a

Upon solving, this gives you=115cm/s and a=-15cm/s/s

So, velocity at the end of 7 seconds is given by:

v= u + at

115-105=10cm/s

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