A particle under the action of a constant force moves from rest upto 20 seconds. if distance covered in first 10 seconds is s1 and then covered in nest 10 seconds is s2 then ? 1. s1=s2 2.s2=3s1 3. s2=2s1 4. s2=4s1

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Answer 1 · 2017-08-05T13:27:13

The answer is option #2#, #s_2=3s_1#

Let the acceleration be #=a#. It is a constant.

The initial velocity is #u=0#

We apply the equations of motion for the first #10s#

#v=u+at#

#v=0+10a#

Then,

#v^2=u^2+2as#

#100a^2=0+2as_1#

#a=(2s_1)/(100)=s_1/50#

We apply the equations of motion for #20s#

#v=0+20a#

#v^2=u^2+2a(s_1+s_2)#

#400a^2=2a(s_1+s_2)#

#s_1+s_2=200a=200*s_1/50=4s_1#

#s_2=3s_1#