Easy Circular Motion Problem that I can't get right

[intriqet]

The astronaut orbiting the Earth in Figure P4.32 is preparing to dock with a Westar VI satellite. The satellite is in a circular orbit 470. km above the Earth's surface, where the free-fall acceleration (centripetal acceleration) is 8.19 m/s2. Take the radius of the Earth as 6370 km.

Determine the speed of the satellite in km/h.


THis is a circular motion problem where a = v^2/r can be used right?
8.19 m/s^2 converted to km/h^2 = 1061.42 km/h^2

sqrt(1061.424*(470+6370) = 2694.46

my answer was 2694.46; 2690 but the system is telling me that I'm off by a multiple of ten. What am I doing wrong?

 

[semc]

I think your conversion from m/s to km/h is wrong...

 

[tomcue]

It seems like you have the right idea, but there may be a mistake in your calculations. The equation a = v^2/r should be a = v^2/r^2, as the radius is squared in the equation. So, the correct calculation would be sqrt(1061.42*(470+6370)^2) = 2694.46 km/h. This should give you the correct answer. Also, make sure to double check your unit conversions, as that could also be a source of error.