How much electrical energy (in kWh) is needed to heat the water in a well-insulated electric hot water heater of capacity 40gal from 20° C to 50° C (68° F to 122° F)

A33.1 g copper object is launched from a 1.5 m 30° steel incline positioned on the floor by being pulled up a string attached to a 50.0 g mass suspended vertically over a pulley. the object is projected towards a glass table where it lands when it is at the point along its trajectory with the lowest speed. it comes to a halt when it clears the opposite edge of the table. it then falls and lands on 9 physics texts each 5 cm thick that are stacked on the floor on the opposite side of the table. assume that the table does not have a ledge and the rectangular object experiences 0.05 n of air resistance as it falls towards the books. how far and how long did the object travel and how fast does it hit the books. assume that at the moment the copper object leaves the incline, the massless string and ideal pulley break off

What is meant by the statement" the melting poin of glycerine is 13 degree celsius

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of