Ineed attacking this problem a steel ball is dropped onto a hard floor from a height of 1.95 m and rebounds to a height of 1.87 m (assume positive direction is upward)
a. caculate it's velocity just before it strikes the floor
b. calculate it's velocity just after it leaves the floor on its way back up
c. calculate it's acceleration during contact with the floor if that contact lasts .0800ms
d. how much did the ball compress during its collision with the floor, assuming the floor is absolutely rigid

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.