Correct Answer - Option 3 :
\( {2x\over t^2}\)
CONCEPT:
- When a body moves in a straight line under constant acceleration, it follows three equations of motion.
- All unknowns are found by these equations.
- v = u + at;
- s = ut + (1/2) at2
- v2 = u2 + 2as
where u is initial velocity, v is final velocity, a is a constant acceleration, t is time and s is displacement.
EXPLANATION:
Given that bike starts from rest, so initial velocity u = 0; s = x and t = t
using 2nd equation of motion
s = ut + (1/2) at2
x = 0 + (1/2) at2
\(a= {2x\over t^2}\)
So the correct answer is option 3.