Sedimentary rocks often contain
a. fossils
b. igneous rock
c. minerals
d. all of the above

Tungsten-filament lightbulb emits light based on the temperature of the filament. which phenomenon does this demonstrate?

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?