Your mother asks you to carry a load of wood to the fireplace and lower it to the hearth. In doing this you have used your arms as levers. Which statement describes this as a class three lever? Question 13 options:

The wood in your hands was the fulcrum, the load your elbow, and the effort (input force) was supplied by your arm muscles.

The wood was the load in your hands, the fulcrum was your elbow and the effort (input force was supplied by your arm muscles.

The fulcrum was the muscles in your arms, the load was the wood in your hands and the effort (input force) was the elbow.

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?

In science and physics what is the standard unit of measure for speed?

Most short-period comets do not have randomly oriented orbits because