1. TORQUE The turning effect of a force

2. Torque Which way will the door turn? Rachel Julia

3. It depends on the size of the force And where the force is exerted Torque is the turning effect of a force

4. Which position requires least force to turn the crowbar?

5. The turning effect of a force is …… d is the distance from the force to the pivot The units for torque are ………… Nm

7. Equilibrium Something is in equilibrium (or balanced) if……… The net force is zero The net torque is zero

8. Clockwise Torque Anticlockwise Torque If Anticlockwise Torque = Clockwise Torque The see saw is in equilibrium (balanced)

9. Clockwise Torque Anticlockwise Torque = F AC d AC FCFC dCdC

11. Solving Torque Problems. 1)Identify the pivot 2)Identify all the forces acting 3)Work out clockwise and anticlockwise torques 4)Use Hannah is 50 kg, the plank is 6 m, Leo is 1m from the end

12. Solving Torque Problems. 1)Identify the pivot 2)Identify all the forces acting 3)Work out clockwise and anticlockwise torques 4)Use 1 cm 10 cm 20 N

13. pivot. An upward force here, Produces an upward force here. The load on the end is 40 kg The load is 2.0 m from the pivot The blue force is 0.80 m from the pivot. Calculate the size of the blue force

14. The crane has a warning sign. Maximum load at 2 m is 400 kg Maximum load at 1 m is 800 kg Why is this? What’s the maximum load at 0.8 m?

15. Sometimes you have to include the weight of the lever. M = 150 kg 4.0 m You can assume that ALL the weight force acts through the centre of mass. F g = 1500 N

16. Sometimes you have to include the weight of the lever. M = 60 kg M = 150 kg Mass of plank = 30 kg Length of plank = 6.0 m 4.0 m Where is Leo?

17. Why does this crane have a counter weight?

18. The principal of moments

19. Balancing a rule

20. Centre of gravity The point on an object where all its weight seems to be concentrated is called the centre of gravity.

21. Centre of gravity The point on an object where all its weight seems to be concentrated is called the centre of gravity. weight of stand contact force of pivot

22. Stability stablefalls over An object will fall over if the vertical line through its centre of gravity falls outside its base.

23. Is Lara in equilibrium?

24. Toppling bus

25. why can a woman knock the match box over with her nose, but a man can’t?

27. The crane is 40 tonnes and 12m long. The boom is 60m long. Calculate the weight of the load it lifted

28. Two pivot problem Mass of bridge = 500 kg Length of bridge = 10.0 m What happens to the support force as the car moves left??? 4.0 m What is the upward force from the right hand support??

29. Two pivot problem M = 60 kg M = 100 kg Mass of plank = 50 kg Length of plank = 6.0 m 1.0 m What is the upward force from the left hand support?? 1.0 m

30. Excellence Question The boom is 8.0 m long and has a mass of 35 kg. Calculate the Tension in the Rope. 30 o rope boom