The force that every mass exerts on every other mass is called

pull

weight

mass

gravity

Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work)

Which best explains how a heat pump can heat a room? cold air from the house is moved through pipes, where it absorbs thermal energy. warm air from outside is pushed into the house to replace the cold air. combustion warms the air when chemical energy is transferred to thermal energy. fuel is used to move a piston, which pushes warm air into the house.

What substance is the most acidic. lemon juice. tomato juice. sodium hydroxide. water