1. Today’s Kaupapa: 1) Calculate the position of the centre of mass 2) Describe the motion of an object in terms of its centre of mass 3) Analyse 2D collisions using centre of mass Mane, 25 Haratua 2015

2. Warm-up: Where does the pivot need to be placed so that the 4m beam is balanced?

3. Centre of Mass The weight of an object acts down through the object’s centre of mass. If the object is suspended, this is the point at which it will balance Can think of all the mass of the object acting down through this point

4. Board notes – calculating COM positon

5. A 2kg mass is suspended from one end of a 1m ruler and a 3kg mass is suspended from the other end. Calculate the centre of mass. x 2 x 9.81 N3 x 9.81 N 1m – x

6. Activity – use a ruler

7. 1) Axe Throwing 2) MIT demo 3) Board notes – COM motion

11. Finish Activity 7D