Whenever two apollo astronauts were on the surface of the moon, a third astronaut orbited the moon. assume the orbit to be circular and 430 km above the surface of the moon, where the acceleration due to gravity is 1.08 m/s2. the radius of the moon is 1.70 â 106 m?

Missing question:
"Determine (a) the astronaut’s orbital speed v and (b) the period of the orbit"

Solution

part a) The center of the orbit of the third astronaut is located at the center of the moon. This means that the radius of the orbit is the sum of the Moon's radius r0 and the altitude () of the orbit:

This is a circular motion, where the centripetal acceleration is equal to the gravitational acceleration g at this altitude. The problem says that at this altitude, . So we can write

where  is the centripetal acceleration and v is the speed of the astronaut. Re-arranging it we can find v:


part b) The orbit has a circumference of , and the astronaut is covering it at a speed equal to v. Therefore, the period of the orbit is

So, the period of the orbit is 2.45 hours.

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.