What does the 2 mean in the formula 5mg3(po4)2?
a. there are two elements in magnesium phosphate.
b. there are two molecules of magnesium phosphate.
c. there are two magnesium ions in a molecule of magnesium phosphate.
d. there are two phosphate ions in a molecule of magnesium phosphate.

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? how far will the football travel before it lands?

Which is not an example of how an object gains elastic potential energy by stretching? a. jumping on a pogo stick b. pulling on a rubber band c. jumping on a trampoline