Physics Laboratory 5 Rotational Mom

Physics Laboratory 5
Rotational Moment of Inertia
1. Objective
To enhance the understanding of rotation and rotational moment of inertia for
both of particle (point mass) and rigid body. In addition, students must be able to find
rotational moment of inertia and compare it with the theoretical value.
2. Theory and Principle
If the line of the net force passes through the center of mass of the object, it
will cause only translation. However, if the line of the net force hits on the object
along other directions, there will induce the moment of force or torque which leads to
rotation.
In this experiment, we will focus on only the rotation around fixed axis.
Theoretically, in case of very small object (particle or point mass), the induced
torque follows the following relation:
τ = Fr (1)
Where τ = Torque (N.m)
r = radius of rotation (m)
From F = mat
(2)
And at = αr (3)
Substitute (2) and (3) into (1)
τ = m r
2
α (4)
Where at
= Tangential acceleration along the circumference of rotation
(perpendicular to radius of rotation)
α = angular acceleation (rad/s2
)
Figure 5.1 Circular rotation of object with mass m- 2 -
The m r2 is the value which shows the characteristic of rotation. If m r2 is high, it is
required a large amount of torque to induce rotation as well as to stop rotating object.
Therefore, m r2 is the term that informs us about the resistance of rotation or the
rotational moment of inertia.
Then
Rotational Moment of Inertia = 2
I = mr (kg.m2
)
In case of larger object or rigid body, while facing non-zero torque, the
equation of rotation should be the same as the particle. However, the rotational
moment of inertia will be the summation of m r2 of each particle.
For rigid body
Rotational Moment of Inertia = 2
i i
I = Σm r (kg.m2
)
= ∫
I r dm 2
In this experiment, from the previous equation, we can find the theoretical

ผลลัพธ์ (ไทย) 1:

Physics Laboratory 5 moments of inertia of the rotation. 1. Aims to increase understanding rotation and rotational inertia for a moment. both particles (the mass) and erection. Moreover, the Students must be able to find the rotational inertia of the moment. And compared with the theoretical value 2. Concepts and principles of the line of force through the center of mass of the object net. It will translate only the If the line hits the net force on an object. follow other instructions are to make a range of force or torque which leads. rotated in this study We will focus only on constant rotation. theoretically In the case of very small objects. (Particles or the total), to induce. torque according to the following relationship:. Τ = Fr (1) where τ = torque (Nm). R = radius of gyration (m). , from F = Mat (2 ) and a = αr (3). replacement (2) and (3) into (1). Τ = MR 2 = one vote (4) where = acceleration tangential to the rotation. (perpendicular to the radius of rotation). = one vote = acceleation an angular (Rad / S2. ) 5.1 circular rotation of an object with mass m-2. M R2 are the values ​​that characterize the rotation. , if m r2 is highly desired torque to cause rotation to stop. To rotate a lot so m r2 to time, to let us know about rolling resistance or. inertia of the season in the rotation. then inertia in rotation as of = 2. , I = MR (Kg.m2 ) object Large or die While dealing with a non-zero torque. The equations of particle rotation should be similar. however The rotational moment of inertia is the sum of r2 m of each particle. rigid body rotational moment of inertia = 2. , I, I , I = R Σm (Kg.m2 ) = ∫ I r dm 2 in this experiment From the previous equation We can see the theoretical