Up for a swing

No matter what you do in air the maximum height reached by center will remain same by the conservation of energy.

In case of rotation folding the arms change the moment of inertia which leads to increase in angular velocity to keep the angular momentum same...!!

w = v/r (w= angular velocity; v= velocity; r=radius) While spinning on office chair, pulling hands up decreases 'r' and therefore increases 'w'. While swinging, when you pull hands to your chest, 'r' doesn't decrease, so 'w' won't decrease.

In case of chair , pulling hands closer decreases moment on inertia (I) ,so angular velocity increases.But in case of swing no such decrease in I ocuurs ..so there is no use of pulling legs closer.

If you're on a swing you only have a set amount of energy. For the period of time where you're going upwards and you pull your body in, you aren't gaining any energy and we can ignore however much you lose.

The energy that you have gets converted into gravitational potential energy, =mgh. Your "m" doesn't change and neither does g, so your height is entirely dependent upon how much energy you have. Since your energy isn't changing, your maximum height doesn't change.

The reason why it works on the chair and not the swing is because the chair is isolated from any torques (forces acting rotationally) that will change the angular momentum of the system. Thus, decreasing your moment of inertia by pulling your arms in causes an increase in your angular velocity to conserve angular momentum. On the swing, your have many torques acting to alter your angular momentum, whether it's air resistance or gravity.

Think about it. If you're going down the swing you're rotating one way and then when you swing backwards you're rotating the other way. Angular momentum is definitely not being conserved and so bringing your legs in isn't guaranteed to have the same effect.

Thanks for reading!

Here, a person pushes you everytime you come down. So there is an external torque acting and hence the angular momentum is not conserved.

Just in case someone comes up with the reason that for increasing max height linear velocity must increase and for using conservation of linear momentum mass must change which in this case does not the answer must be no. But let me tell you that this reason is wrong as external force on the system is not zero as force of gravity acts on the system.

Simply Angular Momentum is conserved in the previous case. But now the angular momentum is $\boxed {not conserved}$

Think as a pendulum. When the center of mass moved to less length, period decreased and frequency of swing increased. Increase of amplitude of swing requires impulse applied onto direction of motion. There is no change of momentum in the direction of motion which is the direction of swing. Only forces or impulses interact in its perpendicular direction. Therefore, there is no change of amplitude of swing.

When we swing on a swingset, we are able to increase the amplitude of swing as we draw some weight component or apply impulse to direction of swing instead, by body motion with skill. If we see a swing motion like a pendulum to be a cone space circular motion at its base, we can imagine and visualize how the frequency can be constant as a projected component of it being seen for a pendulum.

Answer: $\boxed{No}$

Taking the swingset as a pendulum, pulling the legs up decreases the length of the pendulum which has nothing to do with the amplitude of the motion.

simple explanation to this problem : the axis of rotation is diff. in both the cases to decrease the m.i for office chair, we reduce leg length and for reducing m.i for swing we have to reduce the string length , changing leg orientation will NOT alter m.i of swing ..

In case of chair's motion Angular Momentum is conserved so at any time angular momentum is conserved. By pulling legs in the moment of inertia decreases, so to balance it off angular velocity increases. But this is valid only if there is no external torque acting on the system. But in case of swing there is an external torque so angular momentum is not conserved. So pulling legs in won't help.