Question

A disc of radius 0.4 m and mass 1 kg rotates about an axis passing through it centre and perpendicular to its plane. The angular acceleration is 10 rad/s². The tangential force applied to the rim of the disc is ______.

विकल्प

• 2 N

• 4 N

• 3 N

• 1 N

Answer 1

A disc of radius 0.4 m and mass 1 kg rotates about an axis passing through it centre and perpendicular to its plane. The angular acceleration is 10 rad/s². The tangential force applied to the rim of the disc is 2 N.

Explanation:

Moment of inertia = I = `"MR"^2/2`

`= (1 xx (0.4)^2)/2`

= 0.08 kg-m²

Torque τ = Iα = 0.08 × 10 = 0.8 N-m

τ = rF

`therefore "F" = tau/"r" = 0.8/0.4` = 2N