Posted by Eden on .
A 0.70 kg mass at the end of a spring vibrates 4.0 times per second with an amplitude of 0.15 m.
Determine the velocity when it passes the equilibrium point.
Determine the velocity when it is 0.11 from equilibrium.
Determine the total energy of the system.

Physics 
Eden,
sorry, .11 m from equilibrium.

Physics 
bobpursley,
start with the basic equations.
x=A*sinwt
v= Aw*coswt
a= Aw^2sinwt
at the equilibrium point wt is PI (cosine is max), so VAw you know A, and w=2PI/Period, and period is given (.25sec).
when position is .11,
.11=Asinwt solve for wt, then v= Awcoswt
energy? 1/2 m v^2 where v is vmax, or Aw 
Physics 
Eden,
what is Pl?

Physics 
bobpursley,
PI is 3.14159...

Physics 
Eden,
oh... pi... thanks

Physics 
Anonymous,
how do you know period is .25 sec?

Physics 
Anonymous,
frequency is four times per second! (1 sec divided by four times is .25)