In a compound machine, how could the ideal mechanical advantage be calculated? A. Calculate the ideal mechanical advantage of the first simple machine within the compound machine. B. Combine the ideal mechanical advantages of each simple machine part of the compound machine. C. Combine the ideal mechanical advantage of the first and last simple machine in the compound machine. D. Divide the work output by the work input of the whole machine.

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.

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.