1. A 30N force stretches a spring 15 centimeters. What mass must be attached to the spring so that the system oscillates with a period of 0.785 seconds?

2. A body of mass 2kg is suspended from a spring of negligible mass, and is found to stretch the spring 20 centimeters.

a. What is the spring constant?

b. What is the period if the mass is pulled and released?

c. What is the period if the mass is 4kg?

3. A 1.6 kg mass attached to a spring undergoes single harmonic motion of amplitude of 0.12m and has an energy of 72J.

a. What is the spring constant of the spring?

b. What is the frequency of vibration?

4. A 1.2kg block sliding at 6m/s on a frictionless surface runs into and strikes to a spring. The spring is compressed 0.1m before stopping the block.

a. Find the total energy of the system.

b. Find the spring constant of the spring.

c. Find frequency of vibration.

5. The Sears Tower in Chicago has a mass of about 5x10^8 kg and sways back and fort at a frequency of about 0.1 Hz.

a. What is the spring constant of the Tower?

b. If a gust of wind hits the building with a 4x10^6 N force, by how much is the top of the building displaced?

6. Find the length of a simple pendulum whose period is exactly 1 second at a point on earth where g=9.80 m/s^2.

7. A certain pendulum on earth has a period of 2 seconds. What is the period of the moon, where g=1.7 m/s^2?