If the mass is 35g and the volume is 7ml what is thedenstiy in science

Conventional hot-water heaters consist of a tank of water maintained at a fixed temperature. the hot water is to be used when needed. the drawback is that energy is wasted because the tank loses heat when it is not in use, and you can run out of hot water if you use too much. some utility companies are encouraging the use of on-demand water heaters (also known as flash heaters), which consist of heating units to heat the water as you use it. no water tank is involved, so no heat is wasted. a typical household shower flow rate is 2.50 gal/min (9.46 l/min ) with the tap water being heated from 51.0 ˚f (10.6 ˚c) to 120 ˚f (48.9 ˚c) by the on-demand heater.what rate of heat input (either electrical of from gas) is required to operate such a unit, assuming that all the heat goes into the water?

Plz suppose you increase your walking speed from 6 m/s to 13 m/s in a peroid of 3 s. what is your acceleration you in advance.

Aball with a mass of 1.5 kilograms is tied to the end of a rope. the ball is pulled to a height of 0.5 meters above the ground and released. the ball has joules of potential energy at position b. at position a, all of the energy changes to kinetic energy. the velocity of the ball at position a is meters/second. assume there’s no air resistance.