What makes simple machines useful for people without enough strength to complete a task? a. work is reduced, while time is decreased. b. input force is reduced, while time is increased. c. power is increased, while distance is decreased. d. input force is reduced, while distance is increased.

The average atmospheric pressure on earth is approximated as a function of altitude by the relation patm = 101.325 (1 − 0.02256z)5.256, where patm is the atmospheric pressure in kpa, and z is the altitude in km with z = 0 at sea level. determine the approximate atmospheric pressures at atlanta (z = 306 m), denver (z = 1610 m), mexico city (z = 2309 m), and the top of mount everest (z = 8848 m).