If a body starts from rest (initial velocity of zero) and you want to calculate the time taken for it to reach a given velocity, you can use the equation for uniformly accelerated motion:
v = u + at,
where: v is the final velocity, u is the initial velocity (zero in this case), a is the acceleration, and t is the time taken.
Rearranging the equation, we have:
t = (v - u) / a.
Since the initial velocity is zero, the equation simplifies to:
t = v / a.
Therefore, if you know the final velocity (v) and the acceleration (a), you can find the time taken (t) for the body to reach that velocity by dividing the final velocity by the acceleration.