Question

A trapeze artist of mass M is launched horizontally toward a swing of mass m, which is at rest hanging vertically from hooks in the ceiling. The "system" consists of both the trapeze artist and the swing. During the moment when she grabs (and holds on to) the swing, what quantities are conserved, and why?

Answer 1

Answer:

During the moment when she grabs the swing is conserved the angular momentum and the energy.

Explanation:

The external torques in a system change the momentum or:

$\frac{dl}{dt}=T$

Where dl is the change in the angular momentum, dt the change in the time and T the torque.

So, if the external torques is equal to zero, the mometum is conserved. In this case, there are not external torques in the system therefore the momentum is conserved.

On the other hand, the energy is conserved when there aren't no conservative forces in the system, like friction, so, in this case if we ignore the air resistance the energy is conserved.