Solving Damped Oscillator: Time to Reduce to 0.50 Energy

[zhenyazh]

hi,
i am supposed to solve this excerise and i don't even know where to start.

A mass M is suspended from a spring and oscillates with a period of 0.880 s. Each complete oscillation results in an amplitude reduction of a factor of 0.96 due to a small velocity dependent frictional effect. Calculate the time it takes for the total energy of the oscillator to decrease to 0.50 of its initial value.

even the relevant formulas...

 

[zhenyazh]

the same of this one

A 1.05 kg mass is suspended from a spring, with a spring constant of 161.0 N/m. Find the driving frequency which would cause resonance.

all i need is to know where to start from

 

[zhenyazh]

hi
could some one give me an outline for the first question?
i am have no idea what to do.
and i have a test