The mass of the uniform beam (gray coloured) is 15 kg. Calculate the value of distance x m, that a 20 kg mass must be placed in order for the tension in string A to be twice the tension in string B.
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Answer:
Using principle of moments, and taking moments about A,
sum of clockwise moments = sum of anti-clockwise moments
200 * x + 150 * 4 = F * 8
200x + 600 = 8F --------- (1)
Total upward force = total downard force
2F + F = 200 + 150
3F = 350
F = 116.67 N -------- (2)
Thus, substituting (2) into (1)
200x + 600 = 8 (116.67)
x = 1.67 m
