Editor Staff asked 1 year ago
A ring of radius 7cm is rotating about the central axis perpendicular to its plane. A force acts on it, tangentially, such that it does a work of 10J in a complete rotation. Find the value of that force. `
(a) 0.5/7π N
(b) 35π N
(c) 500/7π N
(d) 0.7 N
The question was asked during an online exam.
This key question is from Dynamics of Rotational Motion about a Fixed Axis in portion System of Particles and Rotational Motion of Physics – Class 11
Select the correct answer from above options
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Editor Staff answered 1 year ago
Correct answer is (c) 500/7π N
Best explanation: Let the force be ‘F’. Work done will be = Tθ,
where T is the torque & is the angular displacement = 2π rad.
Work = Tθ = 10
∴ T(2π) = 10
∴ T = 5/π Nm.
Also, T = r*F
∴ 5/π = 0.07*F
∴ F = 500/7π N.
