An oscillating block-spring system has a mechanical energy of 5.1 J, an amplitude of 0.81 m, and a maximum speed 1.6 m/s. Find the spring constant k of the spring.

What is the mass of the block?

What is the frequency of oscillation?

5.1=1/2kx<2

5.1=1/2k.0.81.0.81 now you can solve