Work, Energy & Power Lesson Plan

A free, ready-to-teach lesson on work, energy, and power: objectives, vocabulary, a 5E lesson flow, energy-conservation demos, common misconceptions, differentiation, and an exit ticket.

🎓 High-school physics⏱️ One 50–60 minute class

Overview

This ready-to-teach lesson introduces work, energy, and power — how forces transfer energy, how kinetic and potential energy convert, and how quickly work is done. It is built for a single 50–60 minute high-school physics period and follows the 5E model (Engage, Explore, Explain, Elaborate, Evaluate).

By the end, students can calculate work and power, apply the conservation of energy, and distinguish kinetic from potential energy. A printable cheat sheet and an auto-graded practice quiz are linked for guided and independent practice.

Learning objectives

Students will be able to:

  • Calculate work using W = Fd and identify when a force does zero work.
  • Distinguish kinetic energy from gravitational potential energy and calculate each.
  • Apply the conservation of mechanical energy to a moving object.
  • Calculate power as the rate of doing work, P = W/t.
  • Connect the work–energy theorem to changes in an object's speed.

Materials

  • Projector or whiteboard
  • Printed cheat sheet (linked below)
  • A ramp and a ball or cart
  • A stopwatch and measuring tape
  • Weights for a stair-climb power activity (optional)
  • Devices for the online practice quiz (optional)

Key formulas & terms

Work Done by a Constant Force: The work \(W\) done by a force \(F\) over a displacement \(d\) at an angle \(\theta\).

$$W = Fd\cos(\theta)$$

Work-Energy Theorem: The net work \(W_{net}\) done on an object equals its change in kinetic energy \(\Delta KE\).

$$W_{net} = \Delta KE$$

Kinetic Energy: The energy \(KE\) of an object due to its motion, where \(m\) is mass and \(v\) is velocity.

$$KE = \frac{1}{2}mv^2$$

Gravitational Potential Energy: Energy \(PE_g\) stored based on vertical position \(h\) in a gravitational field.

$$PE_g = mgh$$

Where: \(g\) = acceleration due to gravity (approx. \(9.8 m/s^2\) on Earth)

Elastic Potential Energy: Energy \(PE_s\) stored in a spring stretched/compressed by distance \(x\).

$$PE_s = \frac{1}{2}kx^2$$

Where: \(k\) = spring constant

Total Mechanical Energy: Sum of kinetic and potential energies.

$$E_{total} = KE + PE_g + PE_s$$

Power: The rate at which work \(W\) is done or energy is transferred over time \(t\).

$$P = \frac{W}{t}$$

Work Done by Gravity: The work done by the gravitational force as an object moves from initial height \(h_0\) to final height \(h_f\).

$$W_{gravity} = mg(h_0 - h_f)$$

Work by Non-conservative Forces: The net work \(W_{nc}\) done by non-conservative forces equals the change in total mechanical energy.

$$W_{nc} = E_f - E_0$$

Where: \(E\) = total mechanical energy (KE + PE)

Power (Energy Change): Power is also defined as the rate at which energy changes.

$$P = \frac{\Delta E}{t}$$

Work Done by a Variable Force: The work done is equal to the area under the graph of the force component \(F\cos\theta\) versus displacement \(s\).

$$W = \text{Area under } F\cos\theta \text{ vs } s$$

Instantaneous Power: The product of force \(F\) and velocity \(v\) in the direction of the force.

$$P = Fv\cos(\theta)$$

Key vocabulary

Work
Energy transferred when a force moves an object, W = Fd (force along the motion).
Energy
The capacity to do work, measured in joules (J).
Kinetic energy
The energy of motion, KE = ½mv².
Potential energy
Stored energy; gravitational PE = mgh.
Conservation of energy
Energy is not created or destroyed, only transformed from one form to another.
Power
The rate at which work is done, P = W/t, measured in watts (W).
Work–energy theorem
The net work done on an object equals its change in kinetic energy.
Mechanical energy
The sum of an object's kinetic and potential energy.

Lesson flow (5E)

Engage (5 min)

  • Ask whether holding a heavy box still does 'work' in physics. Reveal that with no motion, W = 0 — which surprises most students.

Explore (10 min)

  • Roll a ball down a ramp from different heights; students observe that more height means more speed at the bottom (PE converting to KE).

Explain (15 min)

  • Use the cheat sheet to develop W = Fd, KE = ½mv², PE = mgh, and the conservation of energy, then define power as P = W/t.

Elaborate (15 min)

  • Run a stair-climb power activity: time students climbing stairs and compute each person's power output. Discuss real examples such as engines and athletes.

Evaluate (10 min)

  • Assign the linked practice quiz or the exit ticket below to check understanding.

Common misconceptions

  • ✗ If you hold something heavy, you are doing work.✓ In physics, work requires motion in the direction of the force; holding an object still does zero work.
  • ✗ Energy gets used up and disappears.✓ Energy is conserved — it transforms (for example PE → KE → heat) but is never destroyed.
  • ✗ Power and energy are the same thing.✓ Energy is the total work done; power is how fast that work is done.
  • ✗ Heavier objects always have more kinetic energy.✓ Kinetic energy depends on both mass and speed (½mv²); a light, fast object can have more.

Differentiation

  • Support: provide a formula reference and a solved W = Fd example.
  • Challenge: add friction or heat losses, or combine the work–energy theorem with kinematics.
  • English learners: pair each quantity with its unit and a simple picture.

Assessment & exit ticket

Use the linked practice quiz for a quick auto-graded check, or the exit ticket below. Watch for students correctly identifying when work is zero and tracking energy through a conversion.

Exit ticket:

  1. How much work is done lifting a 10 N book 2 m straight up?
  2. A ball is dropped — what energy conversion happens as it falls?
  3. State the equation for power and its unit.

Homework

  • Describe an everyday example where potential energy converts to kinetic energy, naming each form and where the energy goes.

Standards

  • NGSS HS-PS3-1 — Create a computational model to calculate the change in the energy of one component in a system.
  • NGSS HS-PS3-2 (related) — Develop and use models to illustrate energy at the macroscopic scale (kinetic and potential).

Frequently asked questions

Is this lesson plan free?

Yes — it's free to view and print, with no login.

What grade level is it for?

High-school physics, and it adapts for physical-science courses.

How long does it take?

One 50–60 minute class, using the 5E structure.

What standards does it cover?

NGSS HS-PS3-1 (and related), on modeling and calculating energy changes.

Is there student practice?

Yes — a printable cheat sheet and an auto-graded practice quiz are linked in the plan.

Select a subject

Select a subject from the left panel to begin exploring formulas.