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.

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

Which of the following is an example of motion in two dimensions?

Based on the concept of the wave-like nature of light, huygens' theory of light postulates that the more light was "bent" by a substance the slower it would move while traversing across that substance. a) deflection b) interference c) refraction d) resonance