Q1. In the interstellar space in our galaxy, there is the background magnetic field whose strength is on the order of 1 nT. Interstellar space also contains about 1 hydrogen atom per cubic centimeter. The temperature of interstellar space is about 3K, so hydrogen atoms have a thermal velocity of about 1000 m/s. How does the energy stored in the magnetic field compare with the kinetic energy in a given volume of space?

Q2. A 10.0g bullet is fired horizontally into a 110g wooden block that is initially at rest on a frictionless horizontal surface and connected to the spring having spring constant 152N/m. The bullet becomes embedded in the block. If the bullet-block system compresses the spring by a maximum of 86.0cm, what was the speed of the bullet at impact with block?