Topic Four (1.4): Centripetal Force
Introduction
For many years, air show pilots have thrilled crowds with their loop-the-loops in the sky. Despite being upside down, the pilots remain in their seats. They are pushed inward towards the centre of the loop by a centripetal force. In this topic you will learn about these centripetal forces that act upon objects moving in a circle.
Reading
Edexcel International AS/A Level Physics Student Book 2 pages 19 to 25
Tasks
Complete the following:
- Read pages 19 to 21 of the textbook.
- Study the Practical Skills box on page 21, you can try to do the experiment if you wish.
- Study the worked example on page 20.
WATCH – Race Cars with Constant Speed Around a Curve (Khan Academy) Links to an external site.
WATCH – Centripetal Force (YouTube) Links to an external site.
WATCH – Centrifugal or Centripetal Force (YouTube) Links to an external site.
WATCH – Explanation of Weightlessness in Orbit (YouTube) Links to an external site.
WATCH – Uniform Circular Motion: Banked Roads (YouTube) Links to an external site.
SIMULATION – Carousel (Walter Fendt) Links to an external site.
COMPLETE – Gameboard: Units of Rotary Motion (Isaac Physics) Links to an external site.
- Complete the questions on page 21. You will find the answers in General Resources under the heading Textbook Answers. Download Textbook Answers.
Top Tips
Make sure that you understand the following key points:
- The centripetal acceleration is a result of the centripetal force, both seeking the centre of the circle, thus satisfying Newton’s second law of motion. The force is causing a change in momentum due to the change in direction, not a change in magnitude.
- If the centripetal force is removed from an object in circular motion the object will follow a straight-line tangent to the circle, provided no other forces are acting. This would therefore satisfy Newton’s first law of motion.
- Centripetal force is the resultant force causing the object to follow a circular path.
Key Terms
Add the following key terms with definitions to your word list:
- Centripetal Force
Consolidate
Now consolidate your understanding by working through these additional resources:
- Read the ‘Thinking Bigger’ section on page 22.
- Complete the questions in the two boxes on page 23.
- Complete the exam practice questions on pages 24 and 25. You will find the answers in General Resources under the heading Textbook Answers. Download Textbook Answers.
Quiz
Complete Quiz 01: Further Mechanics. If you score less than 90%, try again.
Assignment
When you have completed all the activities and are fully prepared and feel confident with the material, you should complete Assignment One and submit it to your tutor via Canvas for marking and feedback.