1.Easy
A hand squeezes the handles of a pair of pliers with 120 N each, 90 mm from the pin O. The jaws grip a bolt 35 mm from the pin. Find the gripping force Q on the bolt.
F = 120 Na = 90 mmb = 35 mm
Q = N
Frames & machines worksheet with answers
2.Easy
The bell crank shown turns about the pin O. A vertical force of 200 N acts at A, 150 mm from O, and is balanced by a horizontal force Q at B, 120 mm above O. Find Q.
F = 200 NOA = 150 mmOB = 120 mm
Q = N
3.Medium
The A-frame shown stands on a pin at A and a roller at B, 5 m apart, with its apex pin C 2.5 m high and the horizontal tie DE 1 m above the ground. A vertical load of 8 kN acts on leg AC at K, 1.5 m (horizontally) from A. Find the tension T in the tie.
P = 8 kNAB = 5 mheight of C = 2.5 mheight of DE = 1 mhorizontal distance A to K = 1.5 m
T = kN
4.Medium
The A-frame shown stands on a pin at A and a roller at B, 5 m apart. The legs meet at the pin C, 3.6 m high, and the horizontal tie DE is 0.8 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.
P = 6 kNAB = 5 mheight of C = 3.6 mheight of DE = 0.8 m
C = kN
5.Hard
A toggle press has two equal links AB and BC, each 150 mm long between pins. The joint B sits 20 mm above the line AC. Which downward force F at B produces a horizontal pressing force of 1500 N at the slider C? Neglect friction and weights.
Q = 1500 NAB = BC = 150 mmh = 20 mm
F = N
6.Hard
A uniform horizontal boom AB of weight 0.5 kN is pinned to a wall at A and held by a cable from its end B to the point C on the wall, 1.5 m above A. A load of 15 kN hangs at B. Find the tension T in the cable.
W = 15 kNWb = 0.5 kNAB = 2.5 mAC = 1.5 m
T = kN
Answer key
- 1. Q = 308.6 N
- 2. Q = 250 N
- 3. T = 4 kN
- 4. C = 4.022 kN
- 5. F = 403.6 N
- 6. T = 29.64 kN
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