Question

Can we use equation V=S/t to find instant velocity in every case? Explain your answer.

Answer 1

if a body moves with constant velocity, if the displacement of the body is S in t seconds.

the average velocity, v_avg = S/t

in this case instantaneous velocity = average velocity

= S/t

If the body moves with varying velocity, if the displacement of the body is S in t seconds.

the average velocity, v_avg = S/t

But in this case instantaneous velocity is not equal to average velocity.

we take a very small displacement dS in a very small time interval dt.

then, instantaneous velocity = dS/dt