An uniform disc of mass 20kg having radius 0.5 m the moment of inertia , if it is rotated about a tangent in its plane ___
a) 12.50 Kgm^2
b) 25 Kgm^2
c) 10 Kgm^2
d) 6.25 Kgm^2
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An uniform disc of mass 20kg having radius 0.5 m the moment of inertia , if it is rotated about a tangent in its plane ___
a) 12.50 Kgm^2
b) 25 Kgm^2
c) 10 Kgm^2
d) 6.25 Kgm^2
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Verified answer
Given:
✰ Mass of uniform disc ( m ) = 20 kg
✰ Radius ( r ) = 0.5 m
✰ It is rotated about a tangent in its plane.
To find:
✠ The moment of inertia.
Solution:
Moment of inertia is nothing but the quantity that expresses the amount of torque needed in rotational axis for angular acceleration.
S.I unit of Moment of inertia is kg/m² or kg m⁻²
Here, we will use perpendicular and parallel theorem simultaneously.
➛ mr²/4 + mr²
➛ 20 × (0.5)²/4 + mr²
➛ 20 × 0.5 × 0.5/4 + mr²
➛ 10 × 0.5/4 + 20 × (0.5)²
➛ 5/4 + 20 × 0.5 × 0.5
➛ 5/4 + 10 × 0.5
➛ 5/4 + 5
➛ 6.25 kg/m²
∴ The moment of inertia = 6.25 kg m⁻²
Option d.) 6.25 kg m⁻² is correct ✔
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