READING QUIZ

Torque primarily depends on:

•angular acceleration.•angular velocity.•angular mass.

Rotational Inertia

The resistance to change in rotational motion.

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τ =Iα

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I = mr2

Moment of Inertia = Mass x distance from axis squared

Torque = Moment of inertia x angular acceleration

Figure 8.15Expressions for the rotational inertia of

several objects, each with a uniform distribution of mass over its volume. The letter m is used to

represent the total mass of the object.

Physics of Angular Motion

If the total torque on an object is zero, then it does not rotate, or it rotates at a constant angular velocity.

Physics of Linear MotionIf the total force on an object is zero, then it does not move, or it is in linear motion with constant velocity

CONCEPT Linear Motion Rotational

Inertia m I

Second Law F=ma τ

Momentum P=mv L=I

conservation P=constant,

if F=0.

L=constant,

if τKinetic energy KE=1/2mv2 KE=1/

Fig. 8.16

Physics of Angular Motion

If the net torque on a system is zero, the total angular momentum of the system is conserved.

L=I

L = vectorI = Tensor = vector

Fig. 8.17

Fig. 8.18

Fig. 8.20

Rotational velocity is a vector. Use the right hand rule to find the direction…..

Fig. 8.24