Can you help me check the following questions? 1) A satellite is in orbit at a d
ID: 2255818 • Letter: C
Question
Can you help me check the following questions?
1) A satellite is in orbit at a distance r above Earth's surface. If Earth's radius is R and the period of the orbit is T, what is the satellite's orbital speed?
a) 2pi(R)/T b) 2pi(r)/T c) 2pi(R+r)/T<- (what I think) d) T/2pi(r)
2) When short track speed skaters round a circular curve on a track, they lean inward toward the center of the curve. Which is the best explanation for their use of this technique?
a) it places the skater's weight more directly over the skates b) it creates a force between the ice and skates that acts toward the center of the track c) it places weight on the skate blades and the ice melts d) it reduces the normal force of the ice on the skates, increasing his speed
3) The circular orbit of a space station is changed in such a way that it experiences a lower value of g, which led to this result?
a) orbit closer to earth, increase orbital speed b) orbit farther from Earth, decrease orbital speed c) orbit closer to Earth, decrease orbital speed d) orbit farther from Earth, increase orbital speed
4) Which is best explained by Kepler's second law of planetary motion? a) the increase in orbital speed of Earth as it approaches a position closer to the Sun (I think) b) the fact that all objects orbiting the Sun have orbital periods proportional to their orbital radii c) the observation that all planets have elliptical orbits d) the decrease in the Moon's orbital speed as it approaches a position close to earth
5) The gravitational force exerted on you by Earth is
A) inversely proportional to the ratio of your mass to the mass of earth (I think not) b) much larger than the gravitational force you exert on earth (Newtons 3rd law??) c) exactly equal in magnitude to the gravitational force you exert on earth (I think so) d) independent of your position relative to Earth (NO)
6) A distance planetary system contains two planets (A and B) that orbit a star. The orbital radius of planet B is four times that of planet A; that is, R_B=4R_A. a) what is the orbital speed of planet B relative to A? Show your solution.
b) Explain how the mass of each planet affects its orbital speed.
Explanation / Answer
1) C
2) b
3) b
4) a
5) c
6)
VA = sqrt(G*M/RA)
VB = sqrt(G*M/RB)
= sqrt(G*M/4*RB)
= sqrt(G*M/RB)/2
VB = VA/2
b) orbital speed, vo = sqrt(G*M/r)
M-->mass of planet
r--> radius of the orbit
orbital does not depend on mass of the orbiting object