According to the text in the stimulus materials, Cosmonaut Gagarin’s pencil “obeyed Newton’s first law” and floated out of reach. Using Figures 1-3 in the stimulus materials, select the two statements that best explain Newton’s first law that affects the motion of the pencil. Select one or more: A. The force acting on an object is equal to the mass of that object times its acceleration. B. Motion cannot change without an unbalanced force acting. C. For every action, there is an equal and opposite reaction. D. An object at rest tends to stay at rest, and an object in motion tends to stay in motion, with the same direction and speed. E. The more force, the more the acceleration.

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?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

What property of an object determines its inertia?