Why is the earth's surface warmer than the surface of other planets, like mars?
a. the earth's atmosphere releases heat.
b. the earth's surface receives less energy from the sun's rays.
c. the earth's rotation transfers energy more evenly.
d. the earth's atmosphere traps heat.

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

Greg drew a diagram to compare two of the fundamental forces. which labels belong in the areas marked x, y and z? gravitational force electromagnetic force x. attractive y repulsive z: infinite range x: infinite range y attractive z. repulsive x. always attractive y: infinite range z: attractive or repulsive x. attractive or repulsive y infinite range z: always attractive

Which of the following describes how a microwave heats food