Gravitational Potential and Kinetic Energy

Overview

In this lesson, you will make the link between height, speed, and stored energy explicit.

What You Need to Know

• Revisit the store language briefly, then focus on two named stores that you can calculate.
• Use examples such as falling objects, rollercoasters, or thrown balls to compare height and speed changes.
• Model the kinetic-energy equation and the change-in-gravitational-potential-energy equation separately before combining them in conservation questions.
• Remember that gravitational potential energy change depends on vertical height change rather than total path length.
• Keep unit handling explicit so you work confidently with joules, kilograms, metres, and metres per second.

How to Work Through It

1. Start with a retrieval question on energy stores and transfer language.
2. Introduce and practise the kinetic and gravitational potential energy equations separately.
3. Compare systems where one store decreases while the other increases.
4. Finish with short conservation-of-energy questions involving height and speed changes.

Check Your Understanding

• Check whether you can decide which store increases when an object is lifted and which increases when it speeds up.
• Use a hinge question where you identify whether a change in height or speed will affect the required energy equation.
• Try one kinetic-energy calculation and one gravitational-potential-energy calculation.

Common Mistakes

• Confusing total gravitational potential energy with change in gravitational potential energy. Keep delta h visible.
• Some assume the tallest object always has the most kinetic energy. Contrast height and speed explicitly.
• Squaring the speed in kinetic-energy calculations is a common source of error.

Next Steps

• Set short mixed questions that force you to choose the correct energy equation.
• Carry the idea of useful and wasted transfer into efficiency.