. A 150 pound (68 kg) student races up the stairs, traversing a total height of 12 feet (3.7 meters) in 5.0 seconds. Calculate the power the student expenses in doing work against gravity.

Based on the concept of the wave-like nature of light, huygens' theory of light postulates that the more light was "bent" by a substance the slower it would move while traversing across that substance. a) deflection b) interference c) refraction d) resonance

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?