Реферат: The Physics Of A Yo Essay Research

climbing up the string continues beyond the momentary application of the tug.

As the yo-yo continues to climb back up the string, the angular momentum

(rotational kinetic energy) of the yo-yo is converted back into gravitational

potential corresponding to the increasing height of the center of mass of the

yo-yo. For this reason, the yo-yo’s rotational kinetic energy and, hence, its

rotation rate, steadily decreases as the yo-yo rises. This is, of course, the

reverse of the process when the yo-yo was dropped.

If not for frictional losses, the yo-yo would climb all the way back up the

string to your hand just as its rotational rate decreases to zero. But, due to

friction, the yo-yo does not quite make it all the way back up to your hand

before it stops rotating.

Thereafter, the process repeats, with the yo-yo returning short of its

previous height on each cycle. Eventually, the yo-yo comes to rest at the

bottom.

Of course, as everyone knows, it is possible to keep the yo-yo going

indefinitely by giving it a slight upward pull on each cycle. This pull can be

combined with the tug required to initiate the climb back up the string. The

pull serves to give the center of mass of the yo-yo a little extra kinetic

energy to compensate for frictional losses, so that the

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yo-yo can be kept going indefinitely.

Yo-yos can also be thrown horizontally, or launched in other directions. The

principle of operation is then just the same except that the kinetic energy of

the center of mass, which is converted into spin as the string unwinds, results

from being thrown, rather than from falling through a gravitational potential.