Question

1. Five objects of mass m move at velocity V at a distance r from an axis of rotation perpendicular axis for each to the page through point A, as shown below. Calculate the angular momentum L about that case (L is positive if it is out of the page) a. A. d. A. e. 2. A puck on a frictionless air hockey table has a mass of 5.0 g and is attached to a cord passing througha 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 cord is then pulled from below, shortening the radius to 1.0 m. The new angular velocity (in rad/s) is

Answer 1

Therefore L vector = r vector times P vector = m (r vector times v vector) (a) L vector = m (r vector times v vector) = -m v r (b) L vector = m (r vector times v vector) = m v r (c) L vector = -m v r (d) L vector = m (r vector times v vector) = m v r sin theta Angle between r vector & v vector. (e) L vector = m (r vector times v vector) = m v sin alpha Mass = 5 gm Angular Momentum remain conserved. L_ini = L_Final m_1 v_1 r_1 = m_2 v_2 r_2 m w_1 r^2_1 = m w_2^2_2 w_2 = w_1 r^2_1/r^2_2 = (3) times 2^2/(1)^2 = 12 Therefore w_2 = 12 rad/sec