# Work Done By a Constant Torque - Power & Moment of Inertia - Rotational Motion Physics Problems | Summary and Q&A

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November 4, 2017
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The Organic Chemistry Tutor
Work Done By a Constant Torque - Power & Moment of Inertia - Rotational Motion Physics Problems

## TL;DR

Learn how to calculate work done and average power exerted by a torque in rotational motion using torque, angular displacement, and time.

## Key Insights

• 💦 Work in rotational motion is equivalent to force times angular displacement.
• 🦾 Torque is the rotational equivalent of force and is calculated as force times lever arm.
• 💦 Average power in rotational motion is work divided by time.
• 🦾 Lever arm or moment arm is the distance between the line of action of the force and the axis of rotation.
• 💦 Rotational kinetic energy can be used to calculate work in rotational motion.
• 📐 Inertia and angular acceleration can be used to calculate torque.
• ✊ Average angular speed can be used to calculate average power.

## Transcript

in this video we're going to talk about how to calculate the work done by a constant torque so in this problem we have a constant torque of 50 newton meters and it's applied to a will causing it to make 40 rotations in a time period of 8 seconds calculate the work done by the torque so work we know its force times displacement and angular displacem... Read More

### Q: How can the work done by a torque be calculated in rotational motion?

The work done by a torque can be calculated using the equation work = torque * angular displacement. The torque is the force applied multiplied by the lever arm, and the angular displacement is measured in radians.

### Q: What is the average power exerted by a torque and how is it calculated?

The average power exerted by a torque is calculated by dividing the work done by the time taken. Average power = work / time. Power is measured in watts, and one joule per second is equal to one watt.

### Q: How can the average power exerted by a torque be calculated when given the torque and angular velocity?

To calculate the average power exerted by a torque, multiply the torque by the angular velocity: average power = torque * angular velocity. Angular velocity is measured in radians per second.

### Q: How can the amount of work performed by a torque be calculated in a given time period?

To calculate the work performed by a torque in a given time period, multiply the power exerted by the time taken: work = power * time. Make sure to convert the time into seconds for the calculation.

## Summary & Key Takeaways

• Work done in rotational motion can be calculated using the equation work = torque * angular displacement.

• Average power exerted by a torque can be found by dividing the work done by the time taken.

• In the provided examples, calculations are performed to find the work done and average power exerted in different scenarios.