# Uniform Circular Motion and Centrifugal ForceArabic Physics

### Instructors

Khaled Marashdeh
Physics and Robotics teacher
Dhahran Ahliyya Schools
Dharhan, Saudi Arabia

*This video was sponsored by Saudi Aramco and produced by Sultan Bin Abdel Aziz Science & Technology Center

## Introduction

The objective of this video lesson is to correct the misconception in the students’ understanding of centrifugal force. The lesson will work to clarify this misconception by using Newton's three laws of motion, particularly the law of inertia, and will demonstrate that the only force acting during a uniform circular motion is centripetal force (i.e., towards the center)  - not including the force of gravity. The lesson will involve experiments and activities that enable students to explore and investigate by themselves the fact that centrifugal force does not exist and to confirm that it is just a centripetal force. Students will learn to calculate the centripetal force for an object in a uniform circular motion. Before starting this lesson, students should be familiar with the following:

• Force analysis of any static or moving object or drawing the Free Body Diagram.
• Newton's three laws of motion.
• Knowledge of the following terms: Inertia, uniform circular  motion, acceleration, tangent of a circle, the circumference and the formula to calculate it (2πr), weight and the law to calculate it (w = mg).
• Knowledge of the following symbols for the scientific terms and its measurement units in English language: Force (F) unit (Newton, N), mass (m) unit (kilogram Kg), velocity (v) unit (m / s), radius (r) unit (meter m), time (t) (seconds) the number of cycles (n). Using the value of the acceleration of gravity as (9.8 m/s2) without approximation.

## Instructor Biography

Khaled Marashdeh is a Jordanian teacher working in Saudi Arabia and he has been a teacher for 17 years.  His university major was Physics with a minor in Computer Science, and he also has a degree in Education. He is working to use LEGO educational products in his teaching of physics and is pleased to have been chosen as one of three correspondents worldwide for the Robotics Competition First LEGO League (FLL). Please visit the FLL Blog.