If you drop a rock from 700 meters high, how long will it take the hit the ground? (Remember to make height negative when solving because it is falling)

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance

Estimate of the number of stars in our galaxy

When oxygen reacts with hydrogen, it has the capacity to release 29 kilojoules of energy. inside a fuel cell, oxygen reacts with hydrogen to produce 23 kilojoules of useful energy. the rest of the energy is lost as heat. what's the efficiency percentage of the fuel cell?