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Planet X and a Satellite 
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#1
Dec3110, 10:33 PM

P: 9

1. The problem statement, all variables and given/known data
Planet X has a mass of 6.42x10^20 kg and a radius of 2400km. A satellite with a mass of 1500kg is in orbit around Planet X at an altitude of 300km. a) what is the Force of Gravity? b) What is the acceleration of the satellite while in orbit? c) Find the speed of the satellite in orbit. d) Find the period of the satellite. 2. Relevant equations F = GMm/r^2, maybe f=ma , a = v^2/r?, T= 2 pi r/v 3. The attempt at a solution a) F=GMm/r^2 F=6.67e11*6.42e23*2000/(3400+300)^2 F[tex]\approx[/tex]6.26e9 N ? b) very unsure but can you use f=ma 6.26e9 N=2000a and solve for a or is tht wrong? I was also maybe thingking of using c) v = ? could you use a = v^2/r a(take answer from b) = v^2/(3400+300) and solve for v or is this the wrong equation or wrong values? d)T= 2 pi r/v T = 2 pi (3400+300)/v(answer from c) ??? Thanks! 


#2
Jan111, 12:02 AM

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P: 10,661

Your method is correct, but the numbers you plugged in for the masses and radius of the planet do not much with the data given.
ehild 


#3
Jan111, 12:18 AM

P: 9




#4
Jan111, 12:35 AM

Mentor
P: 11,689

Planet X and a Satellite
There is no magic formula to help with that! 


#5
Jan111, 12:59 AM

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#6
Jan111, 01:07 AM

HW Helper
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P: 10,661

Read the text of the problem and compare with the data you used when calculating the force: the mass of the planet is 6.42x10^20 kg. It is M. You substituted 6.42x10^23 kg for M. The mass of the satellite is 1500 kg. You substituted 2000 kg for m. The radius of the planet is 2400 m. You plug in 3400 m.
ehild 


#7
Jan211, 11:42 AM

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#8
Jan211, 12:03 PM

P: 9

One quick last question. For a = v^2/r and T= 2 pi r/v would r =2400+300 or just 2400?



#9
Jan211, 12:20 PM

HW Helper
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P: 10,661

r=2700 km
ehild 


#10
Jan211, 12:26 PM

P: 9




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