The bell crank shown turns about the pin O. A vertical force of 300 N acts at A, 200 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 A-frame shown rests on a pin at A and a roller at B, 5 m apart. A vertical load of 6 kN acts on leg AC at the point K, 1.5 m (horizontally) from A. Find the vertical reaction By at the roller.
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, 2.5 m high, and the horizontal tie DE is 1 m above the ground. A load of 6 kN acts at C. Find the magnitude of the force C that the pin C exerts on leg BC.
The frame shown has pins at A, B and C; A and C are fixed to the ground 4 m apart, and B is 3 m above the ground and 1.8 m to the right of A. A vertical load of 20 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, 4 m apart. The legs meet at the pin C, 2.4 m high, and are tied by the horizontal bar DE at 1 m. A horizontal force of 20 kN to the right acts at C. Find the tension T in the tie.
The A-frame shown stands on a pin at A and a roller at B, 6 m apart, with its apex pin C 4.5 m high and the horizontal tie DE 1.5 m above the ground. A vertical load of 12 kN acts on leg AC at K, 1.5 m (horizontally) from A. Find the magnitude of the force C that the pin C exerts on leg BC.
Answer key
- 1. Q = 800 N
- 2. By = 1.8 kN
- 3. C = 5 kN
- 4. FBC = 6.696 kN
- 5. T = 17.14 kN
- 6. C = 4.243 kN
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