The bell crank shown turns about the pin O. A vertical force of 200 N acts at A, 300 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 handles of a pair of pliers are squeezed with 200 N each, 90 mm from the pin O, and the jaws grip a wire 24 mm from the pin. Take all forces as perpendicular to the handle. Find the force FO that the pin transmits.
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 2 kN hangs at B. Neglect the weights. Find the magnitude of the pin force A on the beam at A.
The A-frame shown stands on a pin at A and a roller at B, 2 m apart, with its apex pin C 4.5 m high and the horizontal tie DE 1.8 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, 2.4 m high, and are tied by the horizontal bar DE at 1.2 m. A horizontal force of 10 kN to the right acts at C. Find the tension T in the tie.
The frame shown has pins at A, B and C; A and C are fixed to the ground 8 m apart, and B is 2 m high and 3.6 m to the right of A. Member AB carries a vertical load of 12 kN at K, 2.7 m (horizontally) from A, and a horizontal load of 2 kN to the right acts at B on member AB. Find the size of the horizontal reaction Ax at A.
Answer key
- 1. Q = 500 N
- 2. FO = 950 N
- 3. A = 5.657 kN
- 4. T = 1.111 kN
- 5. T = 10 kN
- 6. Ax = 8.01 kN
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