The bell crank shown turns about the pin O. A vertical force of 250 N acts at A, 250 mm from O, and is balanced by a horizontal force Q at B, 120 mm above O. Find Q.
Frames & machines worksheet with answers
The bell crank shown turns about the pin O. A vertical force of 400 N acts at A, 300 mm from O, and is balanced by a horizontal force Q at B, 150 mm above O. Find Q.
The A-frame shown stands on a pin at A and a roller at B, 2.4 m apart, with its apex pin C 2.5 m high and the horizontal tie DE 1.2 m above the ground. A vertical load of 15 kN acts on leg AC at K, 0.3 m (horizontally) from A. Find the tension T in the tie.
The bell crank shown turns about the pin O. A vertical force of 80 N at A (200 mm from O) is balanced by a horizontal force at B (80 mm above O). Find the magnitude of the pin reaction FO.
The beam AB of the wall bracket shown is pinned at A and propped by the strut CD (C is 0.5 m below A). The beam carries a uniform load of 4 kN/m over its full length and a point load of 4 kN at its free end B. Find the force FCD in the strut.
A toggle press has two equal links AB and BC, each 200 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 5000 N at the slider C? Neglect friction and weights.
Answer key
- 1. Q = 520.8 N
- 2. Q = 800 N
- 3. T = 1.731 kN
- 4. FO = 215.4 N
- 5. FCD = 83.12 kN
- 6. F = 752.1 N
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