{"id":3400,"date":"2016-10-10T19:43:31","date_gmt":"2016-10-11T02:43:31","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T07:00:00","slug":"3400","status":"publish","type":"post","link":"https:\/\/www.vernier.com\/til\/3400","title":{"rendered":"Why is my acceleration data so noisy in a Half-Atwood machine?"},"content":{"rendered":"

One experimental set up that is popular for studying Newton’s Second Law is the Half-Atwood machine. In a Half-Atwood machine, a dynamics cart is tied off to a mass hanging over a pulley. As the hanging mass is released, the cart is accelerated down the track. It is a relatively simple to relate the force exerted on the cart to its acceleration.<\/p>\n

When doing a Half-Atwood experiment, it may seem natural to use a Dual-Range Force Sensor<\/a> (DFS-BTA<\/nobr>) to measure force and a Low-g Accelerometer<\/a> (LGA-BTA<\/nobr>) to measure acceleration (or a Wireless Dynamics Sensor System<\/a> (WDSS<\/nobr>) to measure both); with each mounted to the dynamics cart, you can easily record both and plot acceleration vs force (or vice-versa). Such experimental set ups, however, often run into a limitation in the Low-G Accelerometer. Because the accuracy of the accelerometer is +\/- 0.5 m\/s^2 and the acceleration of the dynamics cart in the set up might be as low as 0.1 m\/s^2, the recorded data will be extremely noisy. Turning on the “oversampling” option in the data collection parameters may smooth the data out a bit. <\/p>\n

In other words, the accelerometer is not the right tool for this particular experiment. There are better ways to measure the acceleration in this context.<\/p>\n

A better method would be to use a Photogate<\/a> (VPG-BTD<\/nobr>) with the pulley to calculate position, velocity, and acceleration data. At such low accelerations, the photogate\/ultra pulley will produce much smoother data. (The following article may be helpful in setting up the Half-Atwood machine in with a photogate: How do I attach a Photogate and Ultra Pulley to the end of a Vernier Track?<\/a>) By far, the cleanest data will come from using our Dynamics Cart and Track System with Motion Encoder<\/a> (DTS-EC<\/nobr>); the encoder system measures positions down to the millimeter accurately and produces exceptionally smooth acceleration data.<\/p>","protected":false},"excerpt":{"rendered":"

One experimental set up that is popular for studying Newton’s Second Law is the Half-Atwood machine. In a Half-Atwood machine, a dynamics cart is tied…<\/p>\n","protected":false},"author":43901,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[580,5760,349,5735,1281],"class_list":["post-3400","post","type-post","status-publish","format-standard","hentry","tag-accelerometer","tag-half-atwood","tag-lga-bta","tag-mec-btd","tag-vpg-btd"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/3400","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/users\/43901"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/comments?post=3400"}],"version-history":[{"count":0,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/3400\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/media?parent=3400"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/categories?post=3400"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/tags?post=3400"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}