1. E O Jones ©2011

2. Nodau Sut i dynnu diagram fector. Amcan Lluniwch diagramau fector. Nodi sut y gallwn ni gwirio ein lluoedd deillio o hynny. Objectives Draw vector diagrams. Identify how we can check our resultant forces. Aims Aims How to draw vector diagram.

3. A B C D A B C D R A + + + = BCDR E O Jones ©2011

7. ForcesHorizontal Components Vertical Components 50 N 0 30N30 Cos 60= +1530 Sin 60= 25.981 35N35 Cos 110=-11.97135 Sin 110 = 32.889 15N15Cos 200=- 14.09515 Sin 200 = -5.130 Total=38.938= 53.74 + - E O Jones ©2011

8. From our vector diagram we can see that our calculations are correct. E O Jones ©2011

9. If the plate is free to rotate about the pivot determine the magnitude and direction of the resultant of the coplanar forces acting on the system and also find the perpendicular distance of its line of action from the pivot. E O Jones ©2011

10. The moment is negative if it moves the object in an anticlockwise motion E O Jones ©2011

11. The magnitude of the resultant of the force system is found using Pythagoras theorem and the angular direction of the resultant is found using the trigonometric ratios. The sum of the horizontal and vertical forces are both negative; therefore, the line of action of the resultant force will act down towards the left, as shown. E O Jones ©2011

12. Now from the table the sum of the moments 5.6 - 2.25 Nm = 3.35 Nm. Σ M =R x d or 3.35 = 9.43 x d and d = 3.35 = 0.355m. 9.43 Now because the resulting turning moment is positive the line of action of the resultant must be below the pivot point. E O Jones ©2011

14. Force F (kN) Horizontal component FH Vertical component FV Moment of FH about point A (kNm) Moment of FV about point A (kNm) 15 3 5 4 Totals E O Jones ©2011