Question

a particle moves in a straight line so that, t seconds after passing through a fixed point O, its velocity, v ms^-1, is given by v=20/(2t+4)^2.
Find the velocity of the particle at O and the acceleration of the particle when t=3

Answer 1

for velocity just plug 3 into the equation.
for acc = dv/dt get the derivative of the equation then plug 3.