Plumb Bob
Why is it that at most locations on the Earth, a plumb bob does not hang precisely in the direction of the?
11-16) Why is it that at most locations on the Earth, a plumb bob does not hang precisely in the direction of the Earth's center?
please help, thanks!
In addition to the centripetal effects already mentioned (which keep the bob from pointing at the center of mass), the Earth is not a perfect sphere, nor is the mass distributed in an ideally symmetric way. It's lumpy. As a result, even at the North Pole (where centripetal effects are zero), you might not get a plumb bob exactly pointed at the geometric center. It might point a little bit more towards the Himalayas or something. We're talking differences too small to be noticed with the naked eye, of course, but they can be relevant for sensitive instrumentation.
Aside: to see how the center of mass and the geometric center can be different, consider two tennis balls glued together, but one of them is filled with sand. The geometric center is where they meet, but the center of mass will be pulled over to somewhere inside the sand-filled ball.
 |
 Vintage Brass Plumb Bob w Reel 4 10oz  US $99.99
|
 Vintage Brass Plumb Bob w Reel 45 12oz US $99.99
|
 LS Starrett Plumb Bob Model 177A with Original Box US $19.99
|
 DeWalt DW082K Level brand new dewalt heavy duty self leveling laser plumb bob US $46.01
|
 OTTOMAN TURKISH BRONZE PLUMB BOB US $49.00 |
 VINTAGE LUFKIN 590 PLUMB BOB US $9.99
|
 Old Vintage Large Bass Screw Cap Plumb Bob US $24.99
|
 Old Antique Brass Plumb Bob Carpentry Tool US $19.99
|
 Old Antique Steel Plumb Bob Carpentry Tools US $19.99
|
 Old Antique Brass Plumb Bob Carpentry Tools US $14.99
|
 Starrett 515C Brass Plumb Bob US $9.99
|
 Vintage Metal String Sargent Plumb Bob Carpentry Leveling Straight Line Tool NR US $9.99
|
 12 OZS BRASS PLUMB BOB 3 LONG US $9.00
|
 Rack A Tiers Laser Plumb Bob US $75.00
|
 carpenters plumb bob US $6.00
|
 DeWalt DW082 Laser Plumb Bob US $49.99
|
 Brass Plumb BoB Arrow Shaped and Flat US $8.99
|
 PB 9 Plumb Bob US $204.00
|
 NEW Stanley 77 189 PB2 Self Leveling Laser Plumb Bob with Carrying Case US $59.49
|
 DIETZGEN Antique 10 oz 5 1 2 5724S Steel Plumb Bob w Removable Point its box US $17.99
|
 KE Plumb Bob US $7.00
|
 Vintage Solid Brass Plumb Bob Tool Heavy Transit or Level Screw type 95 oz US $3.99
|
 Antique 6 Plumb Bob 2 lbs 12oz Handmade US $49.99
|
 12 oz 3 Cone Plumb Bob US $9.99
|
 3 2 lbxs 9 oz Plumb Bob US $9.99
|
 VINTAGE PLUMB BOB STRING BOBBIN US $1.99
|
 1 LB 23 OZ weight CAST IRON ANTIQUE Tool Builders Carpentry level plumb Bob US $8.00
|
 ROMAN LEAD PLUMB BOB METAL DETECTING DETECTOR FIND UNCLEANED US $1.56
|
 ANTIQUE OTTOMAN TURKISH SOLID BRASS PLUMB BOB US $300.00
|
 Plumb bob for Wild T2 theodolite Genuine Wild Tripod plumbob US $11.79
|
 Vintage Old PLUMB BOB General Hardware 12OZ Plumb bob US $9.99
|
| Powered by phpBay Pro |
old fashioned tools plumb bob
