There are three types of rocks on Earth. Each rock type forms in a different way. Igneous rocks were the first rocks on Earth. They form from molten rock. Molten rock is rock that has turned to liquid because of extreme heat. Lava is the name for the molten rock that erupts from volcanoes. When molten rock is below the Earth’s surface, it’s called magma. When molten rock—either lava or magma—cools, it hardens into a solid. This forms igneous rocks. Some examples of igneous rocks are granite, obsidian and basalt. Much of Hawaii’s coast is covered in basalt. Waves break the basalt down over time, creating the black sand of some Hawaiian beaches. Which of the following is true about lava and magma?
A. Lava and magma are both types of molten rock.
B. Magma uses waves to break down lava over time.
C. When magma cools and hardens it becomes lava.
D. Magma is called lava when it’s below the Earth’s surface.

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?

Auniform crate c with mass mc is being transported to the left by a forklift with a constant speed v1. what is the magnitude of the angular momentum of the crate about point a, that is, the point of contact between the front tire of the forklift and the ground

Select all the correct answers. which three statements about electromagnetic radiation are true?