Re: How do the laws of pysics apply to trampolines and gymnastics?

The laws of physics apply throughout everything we do but I have chosen a 
few examples to get you going.

The Law of Gravity is a good starting point:

Your weight is the pull of gravity of the massive planet Earth on your 
body.

 So whenever you leave a surface with a jump (beam or floor) you will be 
pulled back down again.

Then there are Newton’ s 2nd and 3rd Laws of Motion:

2nd – if the momentum of an object changes there must be a resultant force 
acting on it. This force is equal to the change in momentum divided by the 
time during which the force occurs.

 So when you land from a vault you can minimise the force on landing by 
making the landing take longer. This is why we bend our knees on landing 
or use crash mats (as you bend or the mat ‘crumples’ it increases the 
collision time).

3rd – action and reaction are equal and opposite. 

 The harder you land on a trampoline the harder it will throw you back up 
into the air.

The Law of Friction describes the force that always opposes the motion of 
two surfaces sliding over one another, this force is decreased by 
lubricating (oiling) the 2 surfaces.

 Many gymnasts on parallel or uneven bars use powdered chalk to prevent 
their sweat from lubricating their hands or resin to increase friction 
between their hands and the bars.

Moments of Inertia and the Law of Conservation of Angular Momentum are 
more complex to understand. The Moment of Inertia is the resistance of a 
body to being rotated and depends on body shape, the closer the body is 
kept into the axis of rotation the less resistance it presents.

 So you need less force to initiate a somersault in the tucked position 
than in the straight position

The Law of Conservation of Angular Momentum means that once a body is 
rotating or spinning then its momentum of spin must remain the same. This 
means that if the Moment of Inertia is increased then the speed of 
rotation has to decrease to compensate and vice versa.

 So a trampolinist (or figure skater) can slow down a spin by opening 
their arms out and the reverse, speed up a spin by hugging their arms to 
their body. As they bring their arms close they decrease their Moment of 
Inertia.