Cm 1 circular motion introduction

Circular motion

A-level Physics

Unit G484: The Newtonian World

Circular motion: introduction

A-level Physics

Unit G484: The Newtonian World

Circular motion: introduction

Circular motion video

The wall of death LOs

Circular motion

To do

Draw a diagram showing the forces on the moving car (ignore air resistance).

Q. Which of these forces would exist if the car was stationary?

LO 1: describe motion in a circle in terms of acceleration and force

What’s going on? LOs

Circular motion

Learning objectivesAt the end of the lesson you will be able to:

Lesson focus• An introduction to circular motion

• describe motion in a circle in terms of acceleration and force;• use the equation for speed v = 2πr/T ; • define the radian;• convert angles from degrees into radians and vice versa.

Circular motion

Learning outcomes

All of you should be able to

• explain why an object moving in a circle is accelerating;

• describe the direction of this acceleration;

• explain why this object moves in a circle;

• describe the direction of the resultant force on the object;

• describe everyday examples of circular motion.

Some of you may be able to

• describe the origin of centrifugal forces.

Circular motion LO 1: describe motion in a circle in terms of acceleration and force

Moving in circles LOs

Circular motion LO 1: describe motion in a circle in terms of acceleration and force

Moving in circles LOs

Circular motion LO 1: describe motion in a circle in terms of acceleration and force

Moving in circles LOs

Circular motion

To do

1. Define acceleration.

2. What causes acceleration?

3. In what direction does acceleration happen?

Acceleration - recall LOs

Circular motion

Imagine a car travelling at a constant speed. It moves towards the right and

then, instantaneously, turns through ninety degrees.

u

v

To do

Use vector subtraction to work out the direction of the change of

velocity.

Changing direction is acceleration LOs

Circular motion

u

v

To doNow do the same thing for movement in a circle.

- u

v - u

LO 1: describe motion in a circle in terms of acceleration and force

Changing direction is acceleration LOs

Circular motion

uv

To doRepeat the exercise for a smaller movement.

- u

v - u

In which direction does the force causing the acceleration act as the change in direction becomes smaller?

LO 1: describe motion in a circle in terms of acceleration and force

Changing direction is acceleration LOs

Circular motion

Examples of circular motion LOs