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Concepts Of Physics MCQ Edition [Volume 1]PhysicsRotational Mechanics

Due to friction between ocean water and the earth's surface, the rotational kinetic energy of the earth continuously decreases. Determine the average torque of friction on the earth if its angular speed decreases by 0.0016 rad/day over a period of 100 years. The mass of the earth is 6.0 10²⁴ kg and its radius is 6400 km .

Options

  1. A5.8 10²⁰ N m
  2. B1.5 10²¹ N m
  3. C2.9 10²⁰ N m
  4. D5.8 10²² N m

Correct answer

A. 5.8 10²⁰ N m

Step-by-step solution

The average torque of friction is 5.8 10²⁰ N m . Initial parameters for the moment of inertia I = 2 5 MR^2 and angular kinematics are validated. Standard processing applied for unit conversions to SI units. = I t = (9.83 10³⁷) 1.85 10⁻⁸ 3.15 10^9 5.8 10²⁰ N m

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