The graph below shows time versus temperature for water in a tank after the heater has been switched on. The heater is switched off at A on the graph. (A) The mass of water in the tank is 50kg. What is the amount of heat supplied by the heating coil in the first 20 minutes?

What is friction? how does it affect the motion of an object?

What quantity do units represent in value

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.