Torque and Rotation

# Torque and Rotation - PHY 221 Lab#1 Introduction to...

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PHY 221 Lab 9 Torque and Rotation Leader: Critic: Scribe: Goals : Rotation is a rich subject, and we only scratch the surface of it in PHY 211 and 221. Rotary motion is like translational motion in many ways. Just as we describe ordinary translational motion by the kinematic quantities position (x), velocity (v=dx/dt) , and acceleration (a=dv/dt) , rotation is described by the kinematic quantities angular position ( ), angular velocity (  d /dt , and angular acceleration (  d /dt ) . Just as a force is needed to change the state of translational motion nd Law F=ma ), something called a torque ( ) is needed to change the state of nd Law, I . Here I is moment of inertia . Moment of inertia is equal to m i l i 2 , where the sum is over all mass elements of the extended object ( m i ), and l i is the distance of the mass element to the axis of rotation. There is also angular momentum (L=I ) nd Law can be written as&&& = d L /dt, we see that angular momentum is conserved (L=const) if net external torque on the system is zero ( =0). momentum. Materials: Balance, Screw drivers, Wrench, Hammers Flywheels Rotating platform and set of dumbbells Gyroscope Since in many cases we have only one or two versions of each setup, you and your group will have to rotate to the various pieces of equipment. Do the various activities in whatever order is convenient . Page 1 of 10 PHY 221 Lab #1: Introduction to Measurements 12/28/2009 http://physics.syr.edu/courses/PHY221.07Spring/manuals/torque-and-rotation.html

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Activity: 1. Balance Weigh 1kg mass using a balance (Note: our mass sets are not very precise). Make a sketch of the key parts of a balance. Measure the key dimensions and label them on your sketch. What condition do you look for when you say it is balanced? Which angular quantity is constant? zero? Angular position Angular velocity Angular acceleration nd Law in angular form in your argument) The net torque on the balance beam comes from the torque generated by the mass being measured and from the torque by movable masses on the beam. Torque can be calculated with respect to different reference points. It makes sense to calculate torque with respect to a point the rigid body can rotate about. For example, in case of the balance beam, the suspension point. Torque from the force
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Torque and Rotation - PHY 221 Lab#1 Introduction to...

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