posted by mitch .
A particle moves along the y axis according to y(t)=(3.5 m/s^2)t^2 - (9.0 m/s)t + 5.0 m.
(a) What is the particle's velocity as a function of time?
(b) What is the particle's acceleration at t=2.0 s?
a=dv/dt = 7 m/s²