Please Help with Hooke's spring problem!!!!

[cfsalomon]

A small ball at the end of a Hooke's spring moves according to the law : y(t)=3cos(2πt)
let foward stand for the motion in the positive direction and backwards for the motion in the negative direction. Think about the sign of the velocity v(t) and the sign of the acceleration a(t) at each given time.

is the ball speeding up./down
is the ball moving foward/backwards

at:
t=0.1
t=0.4
t=0.6
t=0.9

 

[HallsofIvy]

What kind of "help" do you want? We have no idea what would help you if you don't do at least enough of the problem to give us an idea of what kinds of mathematics you can do.

Do you know how to find a derivative? Do you know that the instantaneous velocity of an object is the derivative of its position function?