All materials are made up of elements. Which of the following best describes elements?

A.
Mixtures combine in several different ways to make many kinds of elements.
B.
Compounds combine in several different ways to make a limited number of elements.
C.
Elements combine in several different ways to make many kinds of compounds.
D.
Elements are unable to combine in order to make different compounds.

STUDY ISLAND

How much force must a locomotive exert on a 12840-kg boxcar to make it accelerate forward at 0.490 m/s2?

Ineed asap! list 3 examples in which friction us or makes things easier in our daily life. explain the effect of friction for each. *make sure you explain the effect of friction for each example! *

Suppose water is leaking from a tank through a circular hole of area ah at its bottom. when water leaks through a hole, friction and contraction of the stream near the hole reduce the volume of water leaving the tank per second to cah 2gh , where c (0 < c < 1) is an empirical constant. a tank in the form of a right-circular cone standing on end, vertex down, is leaking water through a circular hole in its bottom. (assume the removed apex of the cone is of negligible height and volume.) (a) suppose the tank is 20 feet high and has radius 8 feet and the circular hole has radius 2 inches. the differential equation governing the height h in feet of water leaking from a tank after t seconds is dh dt = − 5 6h3/2 . if the height of the water is initially 8 feet, how long will it take the tank to empty? (round your answer to two decimal places.)