How do Trampolines Get Their Bounce? Because of Newton’s Basic Laws of Motion!
Jumping on trampolines is fun, but did you know that it’s also an excellent illustration of Newton’s Basic Laws of Motion?
There’s a lot going on, physics-wise, when you’re bouncing up and down on a trampoline. You don’t have to be an astrophysicist to understand the basics—let’s take a closer look at trampoline physics, starting with Newton’s laws of motion.
Newton’s Basic Laws of Motion
Newton’s three laws of motion are central to the way a trampoline works:
- Newton’s first law: the law of inertia. An object at rest will stay at rest, or an object in motion will stay in motion, unless acted upon by an external force. This is why you don’t get propelled upward if you simply stand on a trampoline—you have to move your legs (the external force). It’s also why you don’t keep flying upwards into outer space after the first jump—the external force of gravity brings you back down.
- Newton’s second law: acceleration. The acceleration of an object depends on its mass and the net force acting upon it. Basically, this means it requires more force to move a heavier, larger object (adults have to use more energy to bounce on a trampoline than children do).
- Newton’s third law: “for every action, there is an equal and opposite reaction.” This is where you get the bounce! When you push down on the trampoline (or fall downward onto the trampoline bed), Newton’s third law says that an equal and opposite reaction pushes back.
Hooke’s Law and your springs
A trampoline is made up of a round piece of fabric (the trampoline “bed”) and springs that suspend the fabric from a rigid frame. Of these basic components, the springs are what make the magic happen. And it’s all because of Hooke’s Law which states that the force needed to extend a spring is proportional to the length of extension. The heavier the person on the trampoline, the longer the springs extend.
Trampolines get their bounce in the way that Hooke’s law interacts with Newton’s third law of motion. When you exert force on the springs, causing them to extend, then you have an “equal and opposite reaction” coming from the springs themselves. The springs push back with the same force that you exerted, and you’re sent flying into the air.
Want to experience the physics of trampolines in action? Reserve your inflatable bounce house today by calling 403.254.9668.