v=s'=(2/3t^3-4t^2+6)'=2/3*3t^2-4*2t+0=2t^2-8t
a=(2t^2-8t)'=2*2t+8=4t+8;
a=12:4t+8=12;
4t=12-8;
4t=4;
t=4/4=1 (c)
v=s'=(2/3t^3-4t^2+6)'=2/3*3t^2-4*2t+0=2t^2-8t
a=(2t^2-8t)'=2*2t+8=4t+8;
a=12:4t+8=12;
4t=12-8;
4t=4;
t=4/4=1 (c)