# Lab#5 Newton's Laws

Pages: 10 (3242 words) Published: March 5, 2014
﻿Lab 5
NEWTON’S THIRD LAW AND Tension FORCES

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To develop an understanding and consequences of Newton's Third Law. •To consider the characteristics of three different types of passive forces: tension (in strings, ropes, springs, and chains), normal forces (which support objects affected by gravity), and friction. Overview

5.1An Introduction to Newton’s Third Law
In order to apply Newton’s laws to complex situations with strings, pulleys, inclined planes, and so forth, we need to consider a third force law formulated by Newton having to do with the forces of interaction between two objects. To “discover” some simple aspects of the third law, you should make some straightforward observations using the following equipment:

2 spring scales (Yellow-50N)
1 rod and table clamp

Fig. 5.1. Ways to test Newton’s third law.
5.1.1. Activity: Newton’s Third Law–Forces of Interaction
a.Set up the situations shown in the diagram above and see if there are any circumstances in which the object that is pulling and the object that is being pulled exert different forces on each other. Be sure to do the second case, in which the person on the right pulls so that it accelerates to the right. Does it matter if the right hand is pulling on the system with a net force to the right, causing acceleration? Describe your conclusions below. You will now repeat the same experiment, but this time use electronic force sensors and the computer based acquisition system

b.Obtain two force sensors, a short loop of string, and a rubber band. You may have to wait for another group to finish if there are not enough force sensors. Log into your workstation (username Physics120, no password). Plug one sensor into Port A and the other...