Question
question 9 i need steps
9) A planet is disoovered to orbit around a star in the galaxy Andromeda, with thesme orbital diameter as the Earth around our Sun. that star has 4 times the mass of Sun, what will the period of revolution of that new planet be, compared to the Earth's orbital period? B) twice as much A) one-half as much D four times as much c) one-fourth asmuch 10) What is the gravitational force on a 7o ke Pemce standing on the Earth, due to the Moon? The 100 mass of the Moon is 7.36 x 102kg and the distanceto the Moonis 3E2 x 108 m. D000024 N B) 024N A) 000024 N 11) By how many newtons does the weight of.100-kg person dange when he goesfrom sea level to 11) an altitude of 5000m? The radius of the Earth is 638 106 m.) mean C016 N B) 36 N A 2.6N A satellite of mass 100kg is at a point 3r above the Earth's undac What is 12) The Earth has radius r. D) 61 N fatellite's weight? 9000 N
Explanation / Answer
9. for circular orbit,
gravitational force = centripetal force
G M m / r^2 = m w^2 r
w^2 = G M / r^3
r is same for both planets.
Mstar = 4 Msun
(w_earth / w_planet)^2 = ( Msun / Mstar)
w_earth / w_planet = sqrt(1/4) = 1 / 2
and T = 2 pi / w
sp T_earth / T_planet = 2
T_planet = T_earth / 2
Ans: (A) One - hal as much of earth's period.
