Firstly, describe the reflected anglehidemi said:Homework Statement:: A plane mirror is in a vertical plane and is rotating about a vertical axis at 100 rpm. A horizontal beam of light is incident on the mirror. The reflected beam will rotate at:
The answer is 200 rpm.
Relevant Equations:: 2θ = 2 dθ/dt
If we know the change of angle is twice the incident angle, then the rate of rotation is 2*100 rpm = 200 rpm. Is there a better explanation of it?
I got it. Thanks!collinsmark said:Firstly, describe the reflected anglewith respect toas a function of the angle of the plane.
Secondly, take the derivative.
[Edit: also, your "2θ = 2 dθ/dt" equation is incorrect.]
The formula for calculating rotation rate from change of angle is: rotation rate = change in angle / time. This means that you divide the change in angle (in radians) by the time it took for that change to occur (in seconds).
Yes, rotation rate can be negative. This indicates that the object is rotating in the opposite direction of the initial rotation.
Rotation rate is typically measured in radians per second (rad/s) or degrees per second (deg/s). These units represent the amount of rotation occurring in one second.
Rotation rate and angular velocity are often used interchangeably, but they are technically different. Rotation rate is the measure of how fast an object is rotating, while angular velocity is the measure of the object's rotational speed and direction.
Yes, rotation rate can change over time. This can occur if the object's angular velocity changes, meaning it either speeds up or slows down its rotation. The change in rotation rate can also be affected by external forces acting on the object, such as friction or torque.