You observe a distant galaxy. you find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared. what do you conclude?

What happens to an isotope during radioactive decay?

The built in flash in a compact camera is usally capable of giving correct exsposure for distance up to how many meters?

Abatter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. the ball remains in contact with the bat for 2.0 ms. what is the magnitude of the average force exerted by the bat on the ball?