Quien me puede hacer un examen de física ?

Why is there friction between objects

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?

The electricity that is delivered to our homes from regional generating stations uses high voltage to increase the safety of transmitting electricity to keep the available power the same despite the low current to induce magnetic fields in the wires to increase the magnetic field produced by the current