When a pair of balanced forces acts on an object, the net force that results is
a. equal to zero.
b. greater in size than both forces combined.
c. greater in size than one of the forces.
d. equal in size to one of the forces.

Suppose you have three polarizing filters, with the second at an angle of 42∘ to the first and the third at an angle of 90∘ to the first. by what perfect will the original intensity of unpolarized light be reduced to after passing through all three filters?

An electric power distributor charges residential customers $0.10 per kilowatt-hour (kwh). the company advertises that "green power" is available in 150 kwh blocks for an additional $4 per month. (green power is generated from solar, wind power, and methane sources.) if a certain customer uses an average of 391 kwh per month and commits to one monthly 150 kwh block of green power, what is her annual power bill

1,990,000,000,000,000,000,000,000,000,000 in scientific notation