The velocity of a object is given by equation v(t)=v0−5t+5t2 Acceleration
a=
dv
dt
=
d
dt
(v0−5t+5t2)=−5+10t
at t=0 the acceleration of object a=−5+10(0)=−5ms−2 So, at time t=0, there is deceleration of object. at t=1s,v=v0−5+5=v0ms−1 and a=−5+10=+5ms−2 So, at t=0, there is non zero and positive value of velocity and acceleration.