The star Sirius is moving toward us at 7600 m/s. A line in its spectrum has a frequency of 5.71x10^14 Hz when stationary. How much will the frequency of the line be shifted?
(Answer is x10^10 Hz.)

When an object is heated it contracts. a. true b. false

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?

The energy equivalent of the rest mass of an electron is