In a day, an electrical resistance heater uses 10 kW-h of electricity. In the same day, the heater delivers 9 kW-h of heat to the house in which it is located. Is this possible or is this a perpetual motion machine? If so, what kind? Explain your reasoning.

Which of the following are properties of mechanical waves? check all that apply ⭕️ particles of the medium move back and fourth, but do not move with the wave. ⭕️ the particles of the medium always move parallel to the wave motion. ⭕️ wave motion begins with a disturbance in the medium. ⭕️ waves transport energy from a source outward, away from the source.

The built in flash in a compact camera is usally capable of giving correct exsposure for distance up to how many meters?

Three resistors are connected in series across a 15-v power supply. if the potential drops across resistors 1 and 2 are 4.1 volts and 3.1 volts, what is the exact potential drop (in volts) across resistor 3?