The bell crank shown turns about the pin O. A vertical force of 120 N acts at A, 100 mm from O, and is balanced by a horizontal force Q at B, 150 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, 6 m apart. A vertical load of 12 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, 6 m apart, with its apex pin C 4 m high and the horizontal tie DE 1.8 m above the ground. A vertical load of 15 kN acts on leg AC at K, 0.75 m (horizontally) from A. Find the tension T in the tie.
The bell crank shown turns about the pin O. A vertical force of 300 N at A (120 mm from O) is balanced by a horizontal force at B (100 mm above O). Find the magnitude of the pin reaction FO.
A toggle press has two equal links AB and BC, each 150 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 2500 N at the slider C? Neglect friction and weights.
The A-frame shown stands on a pin at A and a roller at B, 6 m apart. The legs meet at the pin C, 4.5 m high, and are tied by the horizontal bar DE at 1.8 m. A horizontal force of 10 kN to the right acts at C. Find the tension T in the tie.
Answer key
- 1. Q = 80 N
- 2. By = 3 kN
- 3. T = 2.557 kN
- 4. FO = 468.6 N
- 5. F = 502.5 N
- 6. T = 8.333 kN
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