Question

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​

Answer 1

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 ✔

_______________________________

Answer 2

Answer:

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