Civil Engineering - UPSC Civil Service Exam Questions - Discussion

Discussion Forum : UPSC Civil Service Exam Questions - Section 14 (Q.No. 10)
10.
Two particles of masses 21 gm and 28 gm are connected by a light inextensible string which passes over a fixed smooth pulley. The tension in the string in the ensuing motion will be
7 gm. wt
10 gm. wt
12 gm. wt
24 gm. wt
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
2 comments Page 1 of 1.

Jagwinder singh sidhu said:   3 years ago
Let's assume the tension T in the string.
Acceleration a in the string due to different loads,
Consider fbd of 21gm mass.
T-21g = 21a ----> (1)

Considering fbd of 28gm mass
28g - T = 28a ---> (2)
By solving these equations;
a = g/7.
T = 24g.

Chhaya said:   7 years ago
(2 * 21 * 28)/(21 + 28) = 24.
(2)

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