A puck on a frictionless air hockey table has a mass of 5.0 kg and is attached to a cord passing through a hole in the surface as in the figure.The puck is revolving at a distance 2.0 m from the hole with an angular velocity of 3.0 rad/s.The angular momentum of the puck (in kg.m²/s)is A)80 B)20 C)30 D)60 E)50

Question

Quizplus · Accepted Answer

The angular momentum of a rotating object is given by the formula L = Iω, where I is the moment of inertia and ω is the angular velocity. 
The moment of inertia of a point mass rotating at a distance r from the axis of rotation is given by I = mr^2. 
Substituting the given values, 
I = 5.0 kg * (2.0 m)^2 = 20 kg·m^2 
L = Iω = (20 kg·m^2) * (3.0 rad/s) = 60 kg·m^2/s 
Therefore, the angular momentum of the puck is 60 kg·m^2/s, which corresponds to option D.

A Puck on a Frictionless Air Hockey Table Has a Mass