mcq help (1 Viewer)

[Exp]

A satellite circles the earth in an orbit of radius 6,600 km every 90 minutes. The satellite’s average speed is:

A 12.5 km s-1
B 7.7 km s-1
C 3.9 km s-1
D 10.9 km s-1

I used s=d/t to get s= 2pi(6600+6380)^2 / 90x60 but I don't get any of the choices

 

[supR]

This should help.

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[Exp]

ohhh thank you so much!!

 

[pikachu975]

A satellite circles the earth in an orbit of radius 6,600 km every 90 minutes. The satellite’s average speed is:

A 12.5 km s-1
B 7.7 km s-1
C 3.9 km s-1
D 10.9 km s-1

I used s=d/t to get s= 2pi(6600+6380)^2 / 90x60 but I don't get any of the choices

Your answer was right but radius isn't squared and also you don't add 6380 since it already tells you orbital radius.

s = 2pi(6600)/(90x60) gives B