Forces on a plane

Physics Age group: KS3 and KS4: forces

Four forces act on every plane in the sky. See what happens when they balance, and when they do not.

Before you start

Read or play with these Learn topics first.

Choose an airport

Latest weather report (explained in "How do you read an airport weather report?")

Name: ______________________ Date: ____________

Use the live board for this worksheet.

Name the four forces on a plane in level flight.
What must be true about lift and weight for it to stay at the same height?
What happens to lift if the wing is tilted too far? Use the lab on the "How do planes stay up?" page.
Watch a take-off. Which force is the engine adding, and what must it beat?

Ten questions on this lesson. Pupils open the link on any device. Nothing is stored about them.

Teacher notes and answers

Suggested answers. Many will vary with the live data, so check units and working. The curriculum links are a guide only.

Weight, lift, thrust and drag.
They must be equal (balanced), so there is no resultant force vertically and the height does not change.
The air can no longer follow the wing, so lift drops suddenly. This is a stall.
Thrust. It must be bigger than drag so the plane accelerates (resultant force forwards).