A spring pendulum with a mass of 0.9 kg oscillates at an amplitude of 7 cm and makes 20 oscillations in 15 seconds.
What is the force constant of the spring?
What is the maximum speed of the pendulum?
Now we start to force this pendulum to oscillate. Is a forcing frequency of 1.0 Hz good enough to achieve resonance? If not, how would you have to change the mass to achieve resonance?