Rotational Dynamics Equation
Mediumphysics
A flywheel of moment of inertia 0.5 kg·m² is subjected to a constant torque of 2 N·m. If it starts from rest, what will be its angular velocity after 5 seconds?
Select the correct option:
Solution
Incorrect! Answer:
20 rad/s
- Step 1: Angular Acceleration (α): From Newton's law for rotation, τ=Iα.
- α=2/0.5=4 rad/s2.
- Step 2: Angular Kinematics: Use ω=ω0+αt.
- Application:
- ω0=0 (from rest).
- α=4 rad/s2.
- t=5 s.
- Calculation: ω=0+(4×5)=20 rad/s.
- Result: Final angular speed is 20 rad/s.
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About This Question
- Subject
- physics
- Chapter
- rotational motion
- Topic
- rotational dynamics equation
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
20 rad/s
- Step 1: Angular Acceleration (α): From Newton's law for rotation, τ=Iα.
- α=2/0.5=4 rad/s2.
- Step 2: Angular Kinematics: Use ω=ω0+αt.
- Application:
- ω0=0 (from rest).
- α=4 rad/s2.
- t=5 s.
- Calculation: ω=0+(4×5)=20 rad/s.
- Result: Final angular speed is 20 rad/s.
This medium difficulty physics question is from the chapter rotational motion, covering the topic of rotational dynamics equation. It appeared in the 2025 exam.
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