Newton in action

On the subject of luging, it is the perfect place to illustrate some physics. For those unfamiliar with the Skyline complex, the idea is you sit on a small cart and freewheel down a concrete path, negotiating the various bends inconveniently sited to slow your speed. Great fun, and lots of physics.

In fact, I think every school physics class in The Bay of Plenty and Waikato should do a field trip there at least once a year (purely educational, you understand).  You can talk about gravitational potential energy, or simple harmonic motion (the swaying of the chairlift), or Newton’s laws. Here is a rough translation of Newton’s laws in the language of the luge.

1. "An object will remain at rest or continue to move at constant velocity unless an unbalanced force acts on it"  means "If you want to get your cart to go anywhere, stick it on a slope".

2. "The acceleration of an object equals the force on it divided by its mass" means "the steeper the slope, the faster you gain speed"

3. "For every action there is an equal an opposite reaction" means "if you crash into a tree it hurts." (Not that I have experience of such matters, at least not on a luge cart.)

I’m sure some of you can think of some other examples. Given that it appears so obvious, two thoughts still bug me; first,  why did it take someone of the genius of Newton to work this out? and secondly, what would Newton have made of adults sitting on plastic carts hurtling down a hill on a concrete track?

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