What do we need to measure in order to determine a star's luminosity?

Suppose you are walking home after school. The distance from school to your home is five kilometers. On foot, you can get home in 25 minutes. However, if you rode a bicycle, you could get home in 10 minutes. a.

A particle of mass 5kg is pulled along a rough horizontal surface by a string which is inclined at 60° to the horizontal.

Describe what it means to view something from a frame of reference. Give an example to illustrate your explanation.

Astronomers use radio waves to learn about the universe. Radio waves travel light-years through space before reaching Earth. Radio waves must be which type of wave

What is a strong, short-lived magnet created by a looped electrical current.

A solid sphere of radius R has a total charge Q distributed evenly throughout its volume. What fraction of the total charge is located inside a radius R/2?

What is Nothing. (sorry i have been wondering this for a very long time)

What is the speed of a bobsled whose distance-time graph indicates that it traveled 123m in 28s?

Eric has a mass of 80 kgkg. He is standing on a scale in an elevator that is accelerating downward at 1.7 m/s2m/s2. What is the approximate reading on the scale?

Without the force of friction, people would not be able to walk.