If two similar flashlight shine on a wall from the same distance, the spot on the wall becomes brighter. This is due to light wave___ A) absorption
B) diffraction
C) constructive interference
D) destructive interference

If this plastic cup is heated to its melting point, what will eventually happen to all the particles in the plastic? a. the particles will begin to move enough that they slide past each other. b. bonds will form and the liquid will become a solid. c. the spaces between the particles will get smaller. d. the particles will change state and become a crystalline solid.

Let f(x) = x4- 8x2 . find the relativeextrema of this function using the second derivative test.

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.