There's a little problem with your conversion of units for ω. Instead of "rev/s", it should be 3.49 ___/s (?)Quarkn said:Homework Statement
A turntable must spin at 33.3RPM (3.49 rev/s)...
Yup, that's I....to play an old fashioned vinyl record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 2 revolutions, starting from rest? The turntable is a uniform disk of diameter .305m and mass 0.22kg.
Homework Equations
I = 0.5MR²
[itex]\tau[/itex] = [itex]\alpha[/itex]I
[itex]\alpha[/itex] = (ωf-ωi)/t
The Attempt at a Solution
I=(0.5)(0.22kg)(.1525²)=2.56x10^-3 kgm²
Redbelly98 said:There's a little problem with your conversion of units for ω. Instead of "rev/s", it should be 3.49 ___/s (?)
Yup, that's I.
Your book should have even more relevant equations for rotational motion. You want one that involves θ, so that you can use the information that it takes 2 revolutions to get the turntable up to speed. You can check in your textbook for the full list of equations.
The rotational form of Newton's Second Law states that the net torque applied to an object is equal to the object's moment of inertia multiplied by its angular acceleration. In other words, it explains the relationship between force, mass, and acceleration for an object rotating around an axis.
The linear form of Newton's Second Law deals with objects moving in a straight line, while the rotational form deals with objects rotating around an axis. The linear form uses mass and linear acceleration, while the rotational form uses moment of inertia and angular acceleration.
Torque is the measure of the force that causes an object to rotate around an axis. It is calculated by multiplying the force applied by the distance from the axis of rotation. The greater the torque, the greater the object's rotational acceleration.
The moment of inertia is a measure of an object's resistance to rotational motion. It depends on the object's mass, shape, and distribution of mass around the axis of rotation. The moment of inertia can be calculated using various formulas depending on the shape of the object.
The rotational form of Newton's Second Law can be applied in various situations, such as understanding the motion of objects like spinning tops or gyroscopes, designing machines that use rotational motion, and predicting the behavior of rotating bodies in sports, such as a spinning basketball or a figure skater performing a spin.