Space problem- orbital speed (1 Viewer)

[Cookie182]

hmm just lookin over sum past trials from my skool in order to prepare. Havent done orbital spped in ages and we barely did anythin in class on it.

Heres the question- i use the formula and stuff but i get an orbital speed of 6532.56 m/s (i think the formula gives it to u in m/s)

anywayz sounds too big for me

Here is the question-

Question 18- (3 marks)


A satellite has a mass of 250 kg and is orbiting the Earth at an altitude of 3000km. The Earth’s equatorial diameter is 12756 km.

(a) - Determine its orbital speed. (2 marks)









(b) – Compare the orbital speed of a 500 kg satellite in an identical orbit. (1mark)



I used the formula-


V= Sq root GM/r

this formula completely ignores the mass of the sateliite which they give u- i think to trick u- as all objects at the same altitude from the earth orbit at teh same speed independent of their mass i beleived. Anywayz sum 1 hav a go for us

thanxs

 

[Forbidden.]

For (a) I used v = √GM/r from
F = mv²/r = GmM/r²

r = 6378 km (Because r = d/2 plus altitude)
M = 5.98x10²⁴ kg (Known value)
G = 6.67x10¹¹ (Formula/Data Sheet)

v = √ 6.67x10¹¹ x 5.98x10²⁴ / (6378 + 3000)x10³
v = 6521.663622 ...
v = 6521.7 ms^-1


For (b) I say the orbital speed is still the same, the orbital velocity is only dependant on the radius on the same planet.

 

[Cookie182]

For (a) I used v = √GM/r from
F = mv²/r = GmM/r²

r = 6378 km (Because r = d/2 plus altitude)
M = 5.98x10²⁴ kg (Known value)
G = 6.67x10¹¹ (Formula/Data Sheet)

v = √ 6.67x10¹¹ x 5.98x10²⁴ / (6378 + 3000)x10³
v = 6521.663622 ...
v = 6521.7 ms^-1


For (b) I say the orbital speed is still the same, the orbital velocity is only dependant on the radius on the same planet.

Thnxs dude- i got the same answer i guess it must be right. Geez seemed like a hell of a big number thats all- i mean 6521.7 in m/s is huge- iand i thought the further out u got the slower u orbited??

yea for (b) its definately the same as mass is irrelevant- plus its only a one marker.

 

[Cookie182]

Its roughly 23478 km/h

i guess thats right as LEO which are about 200-300 km altitude do nearly 30000 km/h

very fast though for 3000km altiutude

 

[Forbidden.]

Apparently the greater the orbital radius the greater the orbital velocity needed.

 

[xiao1985]

Apparently the greater the orbital radius the greater the orbital velocity needed.

Slipped?

v = sqrt (GM/r)

i.e. greater the r, smaller the v .

=p