Concepts Of Physics MCQ Edition [Volume 1]PhysicsRotational Mechanics
A wheel rotating about its axis at a speed of 600 rpm (revolutions per minute) is brought to rest by applying a constant torque for 10 seconds. Determine the angular deceleration and the angular velocity 5 seconds after the torque is applied.
Options
- A1 rev/s ^2 , 5 rev/s
- B10 rev/s ^2 , 50 rev/s
- C60 rev/s ^2 , 300 rev/s
- D2 rev/s ^2 , 10 rev/s
Correct answer
A. 1 rev/s ^2 , 5 rev/s
Step-by-step solution
Initial angular velocity, ₀ = 600 rpm = 600 60 rev/s = 10 rev/s Final angular velocity, = 0 Time taken to come to rest, t = 10 s Using the first equation of rotational motion, = ₀ + t 0 = 10 + (10) = -1 rev/s ^2 The angular deceleration is 1 rev/s ^2 . Angular velocity after 5 s is ' = ₀ + t' ' = 10 + (-1)(5) = 5 rev/s