What kind of situation could possibly have caused less energy to enter the Earth's system than exited it, several billions of years ago

An object weigh 40n in air ,weigh 20n when submerged in water, and 30n when submerged in a liquid of unknown liquid density. what is the density of unknown of liquid?

Inside of a windmill or a dam is a that is used to transform one type of energy into electrical energy. a. motor b. generator c. transformer d. power pack

Atennis player used a tennis racket to hit a tennis ball with a mass of 0.25 kg with a force of 5.25 newtons. how does the force the tennis racket exerted on the tennis ball compare with the force the tennis ball exerted on the tennis racket? a. the force of the tennis racket on the tennis ball is equal in magnitude and opposite in direction to the force the tennis ball exerted on the tennis racket. b. the force of the tennis racket on the tennis ball is equal in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. c. the force of the tennis racket on the tennis ball is less in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. d. the force of the tennis racket on the tennis ball is greater in magnitude and opposite in direction as the force the tennis ball exerted on the tennis racket.