(a) Calculate the magnitude of the gravitational force exerted by Mars on a 80 kg human standing on the surface of Mars. (The mass of Mars is 6.4multiply1023 kg and its radius is 3.4multiply106 m.)

(b) Calculate the magnitude of the gravitational force exerted by the human on Mars.

(c) For comparison, calculate the approximate magnitude of the gravitational force of this human on a similar human who is standing 4 meters away.

(d) What approximations or simplifying assumptions must you make in these calculations? (Note: Some of these choices are false because they are wrong physics!)

-Use the same gravitational constant in (a) and (b) despite its dependence on the size of the masses.

-Treat Mars as though it were spherically symmetric.

-Treat the humans as though they were points or uniform-density spheres.

-Ignore the effects of the Sun, which alters the gravitational force that one object exerts on another.