A particle moves in a straight line with a constant acceleration. It changes its velocity from 10 ms-1 to 20 ms-1 while passing through  a distance 135 m in t second . The value of t is 

(a) 10

(b) 1.8 

(c) 12

(d) 9

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Concept Questions :-

Uniformly accelerated motion


The problem requires kinematics equations of motion. 

Let u and v  the first and final velocities of particle and a and s be the constant acceleration and distance covered by it. 

from third equation of motion 

        v2=u2+2as  202=102+ 2a×135or    a=3002×135=109ms-2

Now using first equation of motion,

                 v=u+ at

or     t=v-ua=20-1010/9=10×910=9s

Difficulty Level:

  • 12%
  • 17%
  • 13%
  • 60%