Centre of Mass (Grade 7 - 9)

Target Language or Knowledge:

What would you use to to find the gravitational line of action? Plumbline Define the centre of mass. The position at which an objects mass can be thought of as concentrated Where is the centre of mass on a ladder? In the middle of the ladder How would you find the centre of mass of a square piece of card? Write the instructions in bullet-point form and use a diagram to help illustrate. How would you find the centre of mass of an irregularly shaped 2D piece of card? Write the instructions in bullet-point form and draw a diagram to help explain your answer. The piece of card used in your investigation can sometimes be called by another name, what is it? Lamina What is the word used to describe the turning effect of a swing or spanner etc? Moment When a suspended object (like a swing) is at rest. Where is its centre of mass positioned? Directly below the point of suspension. How could you make a plumb line? String with a weight tied to one end. How would you test to see that you had found the centre of mass of a symmetrical object? If the object is placed with its centre of mass on the top of the pencil, and it balances. What is a line of action? Line passing though an object in the direction of force on that object. A child is swinging in a playground. The swing lifts away from the resting position (equilibrium position). Why will it return to its resting position directly below the point of suspension? Because it has a turning effect when in the air. CHALLENGE: Where is the centre of mass of a donut? In the centre of the hole