91Ó°ÊÓ

How does modern relativity modify the law of conservation of momentum?

What happens to the mass of water in a pot when it cools, assuming no molecules escape or are added? Is this observable in practice? Explain.

A neutral Ï€-meson is a particle that can be created by accelerator beams. If one such particle lives 1.40×10⁴⁸sas measured in the laboratory, and0.840×10^-18s when at rest relative to an observer, what is its velocity relative to the laboratory?

Suppose an astronaut is moving relative to the Earth at a significant fraction of the speed of light. (a) Does he observe the rate of his clocks to have slowed? (b) What change in the rate of Earth-bound clocks does he see? (c) Does his ship seem to him to shorten? (d) What about the distance between stars that lie on lines parallel to his motion? (e) Do he and an Earth-bound observer agree on his velocity relative to the Earth?