Calculating Force & Torque Generated by Radiative Body

[matthew.jonke]

Hello gents/ladies

I've been pondering on how to calculate the force (N) generated by a radiative body.

My enquiries are still in the initial stage, and it has been a few years since i did any serious physics, hence I was wondering if anyone could help me with calculating:

- the force generated by a body with a particular emissivity given an energy input and;
- calculate the rotational torque generated by such a body (although i assume this is the standard torque calculation once you have the force.

Thank you
Matthew

 

[eljose79]

Hello Matthew,

It's great to see your interest in calculating the force and rotational torque generated by a radiative body! I can definitely help you with these calculations.

First, let's define what a radiative body is. A radiative body is an object that emits electromagnetic radiation, such as light or heat. The force generated by a radiative body is a result of the exchange of momentum between the body and the radiation it emits.

To calculate the force generated by a radiative body, we can use the formula:

F = P/c

Where F is the force (in Newtons), P is the power of radiation emitted by the body (in watts), and c is the speed of light in a vacuum (approximately 3x10^8 m/s). This formula is based on the principle of conservation of momentum, which states that the total momentum of a system remains constant.

Now, to calculate the rotational torque generated by a radiative body, we need to consider the angular momentum of the body. The angular momentum is defined as the product of the moment of inertia (I) and the angular velocity (ω). So, the formula for rotational torque would be:

τ = Iω

Where τ is the torque (in Newton-meters), I is the moment of inertia (in kg*m^2), and ω is the angular velocity (in radians/s).

To determine the moment of inertia for a radiative body, we need to know its shape and mass distribution. This can be calculated using the following formula:

I = ∫r^2dm

Where r is the distance from the axis of rotation to the element of mass (in meters) and dm is the mass element (in kilograms).

I hope this helps you with your calculations! If you have any further questions, don't hesitate to ask. Best of luck with your research.