physics
posted by leeece on .
A block of mass = 0.85 kg is connected to a spring of force constant = 775N/m on a smooth, horizontal surface.
1) Plot the potential energy of the spring from = 5.00 cm to = 5.00 cm.
2) Determine the turning points of the block if its speed at x = 0 is 1.1 m/s
I am so stumped on this problem. Could someone please help?
Thank you!

Use PE = 1/2k(delta x)^2 and the kinetic energy for 1.1 m/s which is 1/2mv^2. Find the kinetic energy and set it equal to 1/2k(delta x)^2 and solve for x. This will give you the x value in meters it takes for the velocity to change direction. One will happen in the positive value and another will be in the negative value. For your problem, it will be 3.85 cm and 3.85 cm.