1. LEVERS Week 8

2. What are Levers? A simple machine that transmits and changes mechanical energy from one place to another Everyday life examples: Pliers Hammer Crowbar Wheelbarrow In biomechanics we are interested in levers within the human body (bones) and extended levers which we use in sport (bats, clubs, sticks, racquets)

3. Examples of Levers

4. Sporting Levers

5. Function of Levers Increase or magnify the force applied (longer force arm) Generate increased speed of movement (longer resistance arm)

6. Elements of Levers All levers consist of three parts: Axis (pivot point, fulcrum) Resistance (load) Force (effort) The position of these parts allows us to classify levers into: First class Second class Third class

7. First Class Levers Axis is located between the resistance and the force See-saw, scissors

8. Second Class Levers Axis is at the end of the lever The resistance is between the axis and force Wheelbarrow, bottle opener

9. Third Class Levers Axis is at the end of the lever Force is between the axis and the resistance The human body has third class levers Leg: running Arm: bicep curl Leg: kicking a soccer ball

10. The Principle of Leverage Velocity is greater at the end of a long lever than at the end of a short lever The longer the lever, the greater the velocity at impact and the greater the momentum developed by the object

11. Activities Cut up and paste the levers from the handout into 1 st, 2 nd and 3 rd lever categories Draw and label the axis, resistance, force and class of the following levers Shovel with a load of dirt on it See-saw with 2 people on it (one light, one heavy) A wheelbarrow full of gravel