Phys 1 Student Workbook.pdf

Name _____________________ Class ______________ Date _________Activity P10: Atwood's Machine(Photogate/Pulley System)Concept DataStudio ScienceWorkshop (Mac) ScienceWorkshop (Win)Newton's Laws P10 Atwood’s.DS P13 Atwood's Machine P13_ATWD.SWSEquipment Needed Qty Equipment Needed QtyPhotogate/Pulley System (ME-6838) 1 String (SE-8050) 1Mass and Hanger Set (ME-8967) 1 Universal Table Clamp (ME-9376B) 1What Do You Think?The purpose of this activity is to study the relationship among force, mass, and accelerationusing an Atwood’s Machine apparatus. What is a real world application of Atwood's Machine?Take time to answer this question in the Lab Report section.BackgroundThe acceleration of an object depends on the net applied force and the object’s mass. In anAtwood's Machine, the difference in weight between two hanging masses determines the netforce acting on the system of both masses. This net force accelerates both of the hanging masses;the heavier mass is accelerated downward, and the lighter mass is accelerated upward.PulleyTTMass 2M1M2Mass 1M1gM2gBased on the above free body diagram, T is the tension in the string, M 2> M 1, and g is theacceleration due to gravity. Taking the convention that up is positive and down is negative, thenet force equations for M 1and M 2are:T1 − M1g = Fnet= M1aT2 − M2g = Fnet= M2( −a)Assuming that the pulley is massless and frictionless, and the string has no mass and doesn’tstretch, let T 1= T 2. Solving for a, the acceleration of the system of both masses, the theoreticalacceleration is g times the difference in mass divided by the total mass:⎛a = g M − M ⎞2 1⎜ ⎟⎝ M 1+ M 2 ⎠P10 © 1999 PASCO scientific p. 63