Trampolines: Fun with Physics

 

Although trampolines appear as solely a fun activity, it is actually a complex system involving physics to allow this “fun” to happen. Bouncing on a trampoline perfectly demonstrates conservation of energy-  Kinetic and Potential energy. Additionally, motion on a trampoline is able to demonstrate all three Newtons Laws of Motion. 

In order to understand why we are able to bounce on a trampoline, we must first look at the Law of Conservation of Motion. Potential Energy (PE) and Kinetic Energy (KE) are what allow us to jump much higher on a trampoline, than we would on the ground- hence the “fun”.

Several equations that help to explain trampoline motion:

E = PE + KE + Q

PE = mgh

PE = ½ KX2 

KE = ½ mv2  

F = -kx (Hooks Law) 

Once an individual has “bounced” on the trampoline, much of the Potential energy store in the trampoline springs (PE = ½ KX2) is converted to Kinetic Energy (KE = ½ mv2).  This KE allows the individual to eventually reach a maximum height, at which then all KE is converted into gravitational potential energy  (PE = mgh), which is eventually converted back into PE of the trampoline springs. 

However, it is important to note that our ability to “bounce harder” aka reach a higher height is dependent on our ability to transfer maximal energy.  Should be obvious - spring specifications (the spring constant, spring length, and number of springs attached) largely impact the trampoline's ability to project an individual upwards. Additionally, it has been noted that an individuals’ strength (ability to produce maximal efficient force on the trampoline) has an effect on the “bounce” height.