Bikash T. Magar

A helicopter flies off, its propellers rotating. Why doesn't the body of the helicopter rotate in the opposite direction?

In the air, there's nothing holding the body of the helicopter still - so the rotor blades spin one direction, butthe torque applied to spin the rotors tries to spin the bodyof the helicopter in the opposite direction. The little rotor on the tail helps keep the body of the helicopter pointed in the same direction.

Why it is much more difficult to balance yourself on a bicycle that is at rest than on one that is rolling?

Balance on a bicycle is a matter of constantly correcting against falls, and it's easier when thespeed is higher because the inertia of moving forward overcomes the need for corrective actions.

A yo-yo falls to the bottom of its cord and then climbs back up. (a) Does it reverse its direction of rotation at the bottom? Explain your answer.(b) What "pulls" the yo-yo back to the top?

Get the answer from Yo Yo Master.

Bikash T. Magar

Rotational Dynamics

A helicopter flies off, its propellers rotating. Why doesn't the body of the helicopter rotate in the opposite direction?

Why it is much more difficult to balance yourself on a bicycle that is at rest than on one that is rolling?

A yo-yo falls to the bottom of its cord and then climbs back up. (a) Does it reverse its direction of rotation at the bottom? Explain your answer.(b) What "pulls" the yo-yo back to the top?

Rotational Mechanics