Bill rowed 30 km upstream against a 2 km/h current and back again in a total of 8 h. How fast can he row in still water

A5 nc point charge is at the origin and a second 3 nc point charge is on the x-axis at x = 0.8 m. find the magnitude and direction of the electric field on the x-axs at x = 0.2 m. you may express the direction by letting positive field mean the positive x direction

As shown in fig. p3.64, a closed, rigid tank fitted with a fine-wire electric resistor is filled with refrigerant 22, initially at 2108c, a quality of 80%, and a volume of 0.01 m3. a 12-volt battery provides a 5-amp current to the resistor for 5 minutes. if the final temperature of the refrigerant is 408c, determine the heat transfer, in kj, from the refrigerant.

What is the difference between mass density and weight density?