Conservation Of Angular Momentum 3d4t2f

Examples of conservation of angular momentum 1. The circus acrobat leaves the swing with his arms and legs extended, with a certain angular velocity about a horizontal axis ing through his centre of mass to enable him to spin around the axis. When he brings his arms and legs closer to his body, moment of inertia (I) decreases. To keep his angular momentum constant (angular momentum L = I ω) his angular velocity increase and he starts spinning faster.

2. A skater starts turning with her arms extended and then pulls them in closer (decreasing moment of inertia) to her sides due to which she spins faster ( making her angular velocity increase)

Along with this her rotational kinetic energy also increases, thereby increasing her energy and hence ability to do work. 3. As diver pushes himself slightly forward he acquires a small angular velocity. Once in air, no external torque acts on the body to change her angular momentum.

When he pulls in her body, moment of inertia decreases to increase his angular velocity which enables him to complete his summersault. While entering into the water again he stretches his body to reduce the angular velocity. 4. A man standing on a platform which can rotate about the z – axis. He holds a rotating wheel in his hand where axis of wheel is along Y-axis. Component about the z- axis is zero. If the wheel is turned so that its axis is parallel to the z – axis, the man must rotate in a direction opposite to wheel’s rotation in order that the angular momentum about the z-axis remains zero.

5. A spinning rugby ball is thrown in such a way that it gains spin about its long axis. Since external forces during its journey in air are constant, angular moment is constant. Torque is also zero and hence its direction does not very and can not travel end over end.

6. Helicopter with single propeller rotates in the opposite direction of the rotor to conserve the angular momentum. However if it has two propellers then one is at its tail. As the helicopter starts, its body has tendency to rotate. To counter balanced it, the propeller rotates in the opposite direction.

7. The angular velocity of air in a tornado goes on increasing as we move towards its centre. It is on of the fact that as the air moves towards the centre, its moment of inertia decreases and hence to maintain its angular momentum, its angular velocity increases.

-----------------------------------------------------------------------*** Equilibrium (of force, energy, potential, angular momentum, moment of inertia) of a body at a point means the sum of all (vectors (i.e force, energy, potential, angular momentum, moment of inertia) is ZERO. If a body has three forces acting on a point then summation of all three forces is equal to zero. -----------------------------------------------------------------------If MA > 1 then distance over which effort is applied becomes greater than the distance over which the load is moved. *** Mechanical advantage is the factor by which a machine multiplies the force put into it. The mechanical advantage can be calculated for the simple machines by using the following formulas: Simple machine - Lever: MA = length of effort arm ÷ length of resistance arm.