As the comet slows down, energy is lost from the system. As the kinetic energy of the system increases, the gravitational potential energy of the system decreases. As the comet's kinetic energy increases, the gravitational potential energy of the system also increases. As the comet slows down, the kinetic energy of the system decreases. External work must be done on the system to speed up the comet.

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue

The discovery of the electron as a subatomic particle was a result of

Which of these has some mechanical energy? a. an atom b. heat inside earth c. a book on a shelf d. the fire from a lit match