PHY_10_16_V2_LP_Moment of inertia of a perfectly rigid body

Long-term plan unit:

School:

Date:

Teacher name:

Grade: 10

Number present:

absent:

Theme of the lesson

Moment of inertia of a perfectly rigid body

Lesson objectives

Use the Steiner theorem to calculate the moment of inertia of material bodies

Using the solution of a problem in angular variables, determine the linear displacement, speed, and acceleration of a rotating particle or a point on a rotating body

Success criteria

Express the rotational kinetic energy as a function of the angular velocity and the moment of inertia, and relate it to the total kinetic energy

Use the Steiner theorem to calculate the moment of inertia of material bodies

Compare analogies between physical quantities characterizing the translational and rotational motion.

To calculate the moment of inertia of a thin hoop, straight cylinder, disk, ball and a rectilinear rod relative to the axis passing through the centre of mass?

Language objectives

Subject-specific vocabulary & terminology:

Impulse of force, the rate of change of momentum, angular momentum, the law of conservation of angular momentum, rotational kinetic energy

Rotational kinetic energy is the energy of a body related to its rotation.

Basic dynamic characteristics of the rotational motion are moment of inertia and angular momentum L

Values instilled in the lesson

Safety, Consideration to others, Co-operation, Opportunity for Life-Long Learning, Academic Integrity and Transparency, Respect for Self and Others

Cross-curricular links

Mathematics in derivation of equations

Engineering Physics and design of rotating objects

ICT skills

Using a Smart board and calculators

Previous learning

Linear kinetic energy, linear inertia, Newton’s laws of motion

Planned stages of the lesson

Planned activities at the lesson

Questions for Teacher to ask/ Points of Discussion

Starter

(5 minutes)

Recap the term inertia. The students will be familiar with linear inertia.

Ask the students for examples of inertia and recall equations.

Introduce the yo-yo toy and discuss the idea of angular inertia.

What is inertia?

Can you give real life examples?

What is the equation that relates to it?

Work towards 1^st Objective

(15 minutes)

An object’s moment of inertia depends on how its mass is distributed relative to its axis of rotation. Different shapes have different moments of inertia. Since a yo-yo is approximately a solid cylinder spinning about an axis through its center we can use the following formula to find its moment of inertia:

Discuss the energy transfers of a yo-yo and link to equations.

Checking of Progress

(5 minutes)

Teacher asks students to solve theoretical problems using the formula provided.

1. Determine the moment of inertia of a yo-yo with a mass of 150 grams and a radius of 1.5 cm.

2. The mass of a yo-yo is 200 grams and its radius is 1.7 cm. How much rotational kinetic energy does a sleeping yo-yo have it makes 2 revolutions each second?

3. A yo-yo of radius 1.5 cm is wound and dropped from a height of 0.8 m. Ignoring friction, how many revolutions does it make each second when it is sleeping at the lowest point?

 4. The yo-yo in the previous problem is given a tug and begins to rise. How fast is it moving when it is 0.4 m above its lowest point?

Work towards 2^nd Objective

(10 minutes)

Ask for a volunteer to hold a meter stick in the centre and attach a weight to the meter stick on each side of the volunteer’s hand. Have the volunteer spin the meter stick. Now slide the weights to the end of the meter stick and have the volunteer again try to twirl the meter stick. It should be much harder to get it going. Although the meter stick had the same amount of mass in both cases, it had more rotational inertia when the weights were farther from the axis of rotation.

Plenary

(5 minutes)

Provide students with problem on moments of inertia and students self assess their answer.

What are three keywords of the lesson?

How do they link together?

Reflection

Were the lesson objectives/learning objectives realistic? Did all learners achieve the LO?

If not, why?

Did my planned differentiation work well?

Did I stick to timings?

What changes did I make from my plan and why?

Use the space below to reflect on your lesson. Answer the most relevant questions from the box on the left about your lesson.