Question

A torque of 20 nm is applied on a wheel for 2 second, the change in angular momentum of wheel is?

Answer 1

Given :

Applied torque = 20 N m

Time interval = 2 s

To Find :

The change in angular momentum of wheel.

Solution :

❖ As per Newton's second law of motion for rotation, Torque is defined as the rate of change of angular momentum of rotating object.

» Torque is an axial vector quantity$.$

» SI unit : N m

» CGS unit : dyne cm

Mathematically, τ = dL/dt

• τ denotes torque
• dL denotes change in angular momentum
• dt denotes time interval

By substituting the given values;

➙ τ = dL / dt

➙ 20 = dL/2

➙ dL = 20 × 2

➙ dL = 40 N m/s