CR 2 12. A horizontal uniform plank is supported by ropes I and IT at points P a

Question

CR 2 12. A horizontal uniform plank is supported by ropes I and IT at points P and Q. respectively, as shown above. The two ropes have negligible mass. The tension in rope 1 is 150 N. The point at which rope I is attached to the plank is now moved to point R halfway between point Q and point C, the center of the plank. The plank remains horizontal Which of the following are most nearly the new tensions in the two ropes? Tension in I Tension in II (A) 75 N (B) 100 N (C) 112.5 N (D) 112.5 N (E) 150 N 225 N 200 N 112.5 N 187.5 N 300 N

Explanation / Answer

Using torque for initial situation,

If we consider point C to be at the middle of beam then

T1*x/2 = T2*x/2 ( I have assumed beam length to be x)

so, T1 = T2

Now, when rope 2 is moved to R, it distance to point C become x/2 / 2 = x/4

T1*x/2 = T2*x/4

T1 / 2 = T2 / 4

T1/T2 = 2/4

T2 = 2T1

So, Choice E seems correct

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.