The bell crank shown turns about the pin O. A vertical force of 120 N acts at A, 300 mm from O, and is balanced by a horizontal force Q at B, 75 mm above O. Find Q.
Frames & machines worksheet with answers
The bell crank shown turns about the pin O. A vertical force of 50 N acts at A, 100 mm from O, and is balanced by a horizontal force Q at B, 100 mm above O. Find Q.
A horizontal beam AB is pinned to a wall at A and propped by the strut CD, pinned to the wall at C, 1.5 m below A. A load of 8 kN hangs at B. Neglect the weights. Find the magnitude of the pin force A on the beam at A.
The frame shown has pins at A, B and C; A and C are fixed to the ground 4 m apart, and B is 4 m above the ground and 1.8 m to the right of A. A vertical load of 5 kN acts on member AB at K, 1.08 m (horizontally) from A. Find the force FBC in member BC.
The A-frame shown stands on a pin at A and a roller at B, 3 m apart, with its apex pin C 3 m high and the horizontal tie DE 1.2 m above the ground. A vertical load of 4 kN acts on leg AC at K, 0.9 m (horizontally) from A. Find the magnitude of the force C that the pin C exerts on leg BC.
A uniform horizontal boom AB of weight 0.5 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 8 kN hangs at B. Find the magnitude of the pin reaction A.
Answer key
- 1. Q = 480 N
- 2. Q = 50 N
- 3. A = 17.94 kN
- 4. FBC = 1.541 kN
- 5. C = 1.562 kN
- 6. A = 16.5 kN
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