4. The airplane rose 1600 ft. and then went down 400 ft. What is the present altitude of the airplane?

a. -1200 ft.
b. +1300 ft.
c. +1200 ft.
d. -1300 ft.

5. A submarine was situated 1940 meters below sea level. If it ascends 730 meters, what is
its new position?

a +1200 meters
b. +1210 meters
c. -1200 meters
d. -1210 meters​

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

the number 100 represents the number of trials in the experiment.

49/100 represents the experimental probability of the coin landing heads up.

step-by-step explanation:

b, 20 yards

step-by-step explanation: