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Section 10.1, 14.2
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State the rotational equivalents of the linear
quantities mass (p. 301, see table 10.2 on p.304), velocity, acceleration, and force (p.306).
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State the 2 types of vector multiplication and
describe the differences between them.
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For rotational inertia or moment of inertia,
state the dominate effect, distance fro the center of rotation or mass.
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Convert between various methods of expressing
rotational velocities.
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Indicate which rotational quantities are vectors
and which are scalars.
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Use the right hand thumb rule to represent
rotational vectors as arrows where the length is proportional to the magnitude
and the arrow head represents the direction. (Figure 10.3, p. 295)
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By looking at the arrows representing rotational
velocity and acceleration, determine if an object's rotation is speeding up or
slowing down.
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By looking at the arrows representing rotational
acceleration determine the direction of the arrow representing the torque
vector.
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Solve problems with rotational kinematics
equations.
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Calculate rotational kinetic energy.
Homework: Questions 1-5 Problems 1, 3, 7. Serway
Metacognition Problem Solving Principle
10.1:
For every linear motion equation and principle there
is a rotational counterpart. In other words if you know the equations and
principles of motion in the linear world you know them in the rotational world.
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Lesson 1
Key Concept:
Every quantity and equation in the linear world has a counterpart in
the rotational world.
Purpose:
Enable students to write rotational equations, given linear
equations addressing similar situations.
Interactive Discussion:
Objective 1-8. List the linear and their corresponding rotational
quantities on the board.
Demo 10.1:
Objective 1, 400 grams of mass taped on the end of a meter stick.
Have students balance the mass on their hand first with the mass
close to the hand and second with the mass as far as possible from
the hand. Which way is easier and why?
In Class Problem Solving:
Objectives 9 and 10
- State the Earth's rotational velocity in RPM,
RPS, tangential velocity, and w.
- Spin down time on a wheel.
- Swinging door problem. q
= 2t^3 - 3t^2 +5t + 7, Find q, w, a
@ t=10 sec
- Calculate the rotational kinetic energy stored
in Earth both in joules and megatons of TNT.
Resources/Materials: Meter
stick, tape, and 2, 200 gram weights. |
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Section 10.3
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State the two key equations which link the linear and rotational worlds.
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Given a wheel's w
solve for its linear velocity and vice versa.
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Given a wheel's a
solve for its linear acceleration and vice versa.
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Find the net torque on a wheel.
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Use the rotational version of Newton's second
law. (See example 10.9, p.307.)
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Calculate the max torque which can be exerted on
a wheel without making it spin.
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Solve yo-yo problems.
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Solve pulley problems. (See example 10.12,
p.310.)
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Calculate the acceleration of the free end of a
rod which rotates around a fixed pivot on one end as it falls. (See example
10.10, p.309.)
Metacognition Problem Solving Principle
10.2:
There is an equation which links the linear world to the rotational world for
every property of motion in physics. The three most useful ones are shown below:
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1) |
v |
= |
rw |
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2) |
a |
= |
ra |
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3) |
t |
= |
(F) x (r) |
Homework: prob. 33, 35, 37, 59 Serway
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Lesson 2 Key Concept:
There are three key equations which link the linear and rotational worlds.
Purpose: Show
how rotation and linear motion interact.
- Interactive Discussion:
Objective
In Class Problem Solving:
Objectives
- See objectives 12 to 19
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Section 10.3
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Solve swinging rod problems.
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Solve yo-yo problems using conservation of
energy.
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Calculate the power required to turn a winch.
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Solve belt problems.
Homework: prob. 45, 47 Serway
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Lesson 3 Key Concept:
Rotational Work, Power, and Energy
Purpose: Apply
conservation of energy to rotational problems
- Interactive Discussion:
Objectives 11 to 14
In Class Problem Solving:
Objectives 11 to 14
- See objectives 11 to 14.
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Formal Lab Investigation |
Title |
Investigation
of a Belt Drive |
Category |
Mechanics |
Purpose |
Determine
if the belt on a 5.25 inch floppy disk drive is slipping. |
Models |
V
= r(w) |
Overview |
Use
a strobe light to measure the rotational velocity of the wheels in a
floppy disk drive. |
Safety
Issues |
Do
not flash the strobe in anyone's eyes. Do not short circuit the
power supplies. They can burn up. Do not touch any pieces of
rotating equipment. This can seriously injure fingers. |
Equipment
Limitations |
The
floppy drives can be damaged if run too fast for a long period of
time. |
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