Question

the displacement of a particle at time t along x-axis is given by x=p+qt+rt2-st4 .IT'S velocity at t=0

Answer 1

$v = \frac{dx}{dt}$
$\frac{dx}{dt} = 0 + q + 2rt - 4t ^{3}$
put t=0
v=q

Answer 2

dx/dt =-4st3+2rt+q
v=dx/dt = -4st3+2rt+q
Velocity at t=0
velocity = q m/s