Question

Two string are tied 2 m apart on a rod and on the other end a mass 200 g is tied as shown in fig. Each string is 1.25 m long. Find the tensions T₁ and T₂ if the rod is rotated with 60 rpm.

• A. 6N, 3N
• B. 6.25 N, 3.75 N
• C. 4.25 N, 5.75 N
• D. 5.25 N, 4.75 N

Answer 1

Answer: (B)

6.25 N, 3.75 N

Answer 2

Resolve T₁ and T₂.

Look into Fig. carefully

T₁ cos θ + T₂ cos θ = mrω2

T₁ sin θ = T₂ sin θ + mg

or (T₁ + T₂) (0.6) = 0.2 × (3/4)(2π)²

or T₁ + T₂ = 10

T₁ – T₂ = mg/sin θ = 0.2×10/0.8 = 2.5

Solving T₁ = 6.25 N and T₂ = 3.75 N