The bell crank shown turns about the pin O. A vertical force of 200 N acts at A, 150 mm from O, and is balanced by a horizontal force Q at B, 100 mm above O. Find Q.
Frames & machines worksheet with answers
The A-frame shown stands on a pin at A and a roller at B, 3 m apart. The legs meet at the pin C, 4 m high, and are tied together by the horizontal bar DE at a height of 1.5 m. A load of 4 kN acts at C. Find the tension T in the tie DE.
In the toggle clamp shown, two equal links AB and BC are pinned together at B, and each makes 15° with the line AC. A downward force of 500 N is applied at B. The slider C presses on a workpiece. Neglecting friction and weights, find the horizontal clamping force Q.
The A-frame shown stands on a pin at A and a roller at B, 4 m apart. The legs meet at the pin C, 2.4 m high, and the horizontal tie DE is 0.8 m above the ground. A load of 10 kN acts at C. Find the magnitude of the force C that the pin C exerts on leg BC.
A uniform horizontal boom AB of weight 3 kN is pinned to a wall at A and held by a cable from B to the point C on the wall, 2 m above A. A load of 6 kN hangs at B. Find the magnitude of the pin reaction A.
A toggle press has two equal links AB and BC, each 150 mm long between pins. The joint B sits 20 mm above the line AC. Which downward force F at B produces a horizontal pressing force of 3000 N at the slider C? Neglect friction and weights.
Answer key
- 1. Q = 300 N
- 2. T = 1.2 kN
- 3. Q = 933 N
- 4. C = 8.004 kN
- 5. A = 7.649 kN
- 6. F = 807.2 N
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