The bell crank shown turns about the pin O. A vertical force of 400 N acts at A, 120 mm from O, and is balanced by a horizontal force Q at B, 75 mm above O. Find Q.
Frames & machines worksheet with answers
A horizontal beam AB is pinned to a wall at A and propped by the strut CD, pinned to the wall at C, 1 m below A. A load of 12 kN hangs at the free end B. Neglect the weights. Find the force FCD in the strut.
The A-frame shown stands on a pin at A and a roller at B, 6 m apart, with its apex pin C 4 m high and the horizontal tie DE 2 m above the ground. A vertical load of 8 kN acts on leg AC at K, 0.75 m (horizontally) from A. Find the tension T in the tie.
The A-frame shown stands on a pin at A and a roller at B, 2 m apart. The legs meet at the pin C, 2.5 m high, and the horizontal tie DE is 1.2 m above the ground. A load of 12 kN acts at C. Find the magnitude of the force C that the pin C exerts on leg BC.
A toggle press has two equal links AB and BC, each 80 mm long between pins. The joint B sits 15 mm above the line AC. Which downward force F at B produces a horizontal pressing force of 1000 N at the slider C? Neglect friction and weights.
The A-frame shown stands on a pin at A and a roller at B, 2 m apart. The legs meet at the pin C, 2.4 m high, and are tied by the horizontal bar DE at 1.2 m. A horizontal force of 6 kN to the right acts at C. Find the tension T in the tie.
Answer key
- 1. Q = 640 N
- 2. FCD = 34.61 kN
- 3. T = 1.5 kN
- 4. C = 7.57 kN
- 5. F = 381.8 N
- 6. T = 6 kN
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