Asample of a solid substance has a mass m and a density ? 0 at a temperature t0. (a) find the density of the substance if its temperature is increased by an amount ? t in terms of the coefficient of volume expansion ? . (use any variable or symbol stated above as necessary.) (b) what is the mass (m') of the sample if the temperature is raised by an amount ? t? (use any variable or symbol stated above as necessary.)

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.