Kids have the know-how, but they can’t tell the principal.
“How can you go so high?”
Some principles are difficult to describe in words in the world, even if everyone knows.
I think one of them is how to ride a swing.
Can you explain how to ride a swing with a physics equation?
Standing or sitting at the midpoint of a moving swing changes the length of the pendulum.
In other words, a swing can be thought of as a ‘pendulum that can change its length‘.
Consider the pendulum that moves, as shown in the picture below.
When you going down from A to O
The reduced potential energy equals the increased kinetic energy.
When you going from O to B.
Reduced kinetic energy equals increased potential energy.
Change in angle while moving from A to B
The speed at ‘O’ does not changed,
How to ride a swing well?
When going down, we need to increase the length of . (= sit down.)
Conversely, when you go up, you have to stand up.
For example, let’s calculate the increase in angle by substituting the following condition.
- (Angle of starting point)
In this case, the angle is increased by about 1.24 times.