Question

a body moves from rest with uniform acceleration and travels 270 m in 3 seconds find the velocity of the body at 10 seconds from the start

Answer 1

here the main thing is uniform acceleration which means that "a" would be constant such that acceleration after 3s would be equal to acceleration after 10 s so from 1st case we will find the acceleration from 2nd equation of motion. i.e s=ut + 1/2 at^{2} from this equation we will find 
   1/2 at2 = s-ut 
  a= 2(s-ut)/t2
  here initial speed u=0 so ut = 0
  a= 2*270/3*3 
  a = 60m/s2 - (1)
  Now we know that v= u+at
from eqn 1 a= 60m/s2
 so here v= 0+ 60*10
 v=600m/s

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