A disc of metal is melted to recast in the form of a solid sphere. The...
Moment of inertia will decrease, because
Id=1/2mr2 and Is=2/5mr2,
the radius of sphere formed on recasting the disc will also decrease.
A disc of metal is melted to recast in the form of a solid sphere. The...
Moment of Inertia:
The moment of inertia is a measure of an object's resistance to changes in its rotational motion. It depends on the mass distribution of the object and the axis of rotation. For a solid sphere, the moment of inertia can be calculated using the formula:
I = (2/5) * m * r^2
Where I is the moment of inertia, m is the mass of the sphere, and r is the radius of the sphere.
Moment of Inertia of a Disc:
The moment of inertia of a disc can be calculated using the formula:
I = (1/4) * m * r^2
Where I is the moment of inertia, m is the mass of the disc, and r is the radius of the disc.
Conversion of Disc to Sphere:
When the disc is melted and recast into the form of a solid sphere, the mass remains the same. However, the mass distribution changes as the disc is transformed into a sphere.
Effect on Moment of Inertia:
The moment of inertia of a sphere is given by the formula:
I = (2/5) * m * r^2
Comparing this with the moment of inertia of the disc, we can see that the moment of inertia of the sphere is greater.
Therefore, by recasting the disc into a solid sphere, the moment of inertia about a vertical axis passing through the center increases.
Explanation:
When the disc is melted and recast into a solid sphere, the mass remains the same. However, the distribution of mass changes. In the case of a disc, the mass is concentrated towards the outer edge, resulting in a smaller moment of inertia. On the other hand, in the case of a sphere, the mass is distributed more evenly, resulting in a larger moment of inertia.
So, by recasting the disc into a solid sphere, the moment of inertia about a vertical axis passing through the center increases.
Conclusion:
The moment of inertia about a vertical axis passing through the center would increase when a disc of metal is melted and recast in the form of a solid sphere.