The spectrum of a star shows an equivalent set of dark absorption lines to those of the Sun, but with one exception: Every line appears at a slightly shorter wavelength; each is blueshifted. What conclusion can be drawn from this observation

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

Which safety measures should you follow during a thunderstorm? check all that apply. (a) avoid touching anything that conducts electricity. (b) avoid touching a person who has been struck by lightning. (c) go outside. (d) keep your computer turned off. (e) stay out of water. (f) stay inside.

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is