Canadarm2 and metric units

Comments and questions about the APOD on the main view screen.
Martin Davis
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Joined: Mon May 22, 2006 8:08 am
Location: New Zealand

Canadarm2 and metric units

Post by Martin Davis » Mon May 22, 2006 8:16 am

Canadarm2 is a nifty piece of machinery, but a 116 tonne capacity?? Pushing the envelope, I would have thought. Canada must have some impressive buses if the original specification was 'oh, about as big as a bus'.

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Joined: Mon May 22, 2006 8:58 am
Location: Florida

Texas Size

Post by freggo » Mon May 22, 2006 9:02 am

and they say everything is BIG in texas.... but yeah, a 116t Bus, now that I'd like to see. Even if they meant 116000lb... that would still be 52t; one hell of a Greyhound that would be :-)

But thanks for the great photo !

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Joined: Mon May 22, 2006 10:38 am
Location: China

Post by Rincewind » Mon May 22, 2006 10:48 am

The figures do seem to be open to question. The frist Canadarm on the shuttle can move 65,000 pounds (29 tonnes) - source wikipedia. The new one you would expect to move more than that but just how much I don't know. The wikipedia page for the Canadarm reports the same facts as this site. I suspect one was copied form the other. But wikipedia also gives the lb capacity to ruling out wrong units.

The mass it's self, quoted at 116,000kg is not unbelievable. Remember no gravity. Also no air resistance. So even a small force can move a big mass. The referance to a bus though is unusual. A bus might weigh 16t fully loaded. So I think it's the comparason that is wrong not the figures.

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Joined: Tue Oct 12, 2004 5:25 pm

Final solution to "speed of light problem"

Post by makc » Mon May 22, 2006 11:11 am

Just found this "metric units" thread and thought I would post somewhat interesting unrelated stuff:
Someone wrote:Is c, the speed of light in vacuum, constant?
At the 1983 Conference Generale des Poids et Mesures, the following SI (Systeme International) definition of the metre was adopted:
The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.
This defines the speed of light in vacuum to be exactly 299,792,458 m/s. This provides a very short answer to the question "Is c constant": Yes, c is constant by definition!