Jumping on a trampoline looks like an easy and mindless activity but there’s so much more to it than you think. The rebounding effect of a trampoline has several lessons in physics that you could learn from. It’s all about questioning what is happening around you. Why do you bounce the way you do? Or why does someone else able to bounce better or worse than you? Let’s find out all the answers.
Experience In Action What Newton Stated
His First Law
When you get on a trampoline you do not automatically start bouncing. You have to make the first move of jumping before you can get the bounce. So there is a need for an external force that is you jumping. Similarly, when you start jumping on the trampoline you do not fly off into the sky but land back on the trampoline for another bounce. This is because of another external force, the Earth’s gravity that keeps you grounded. The above 2 things are summarised in Newton’s 1st Law: An object will stay at rest or stay in motion unless acted upon by an external force.
Second Law and Acceleration
Recall the scenario where you and some older people from your family were bouncing on the trampoline. You might have noticed that the kids in the family were able to jump higher on the trampoline than the older and heavier people. It is because it requires more effort for someone who is heavier to jump higher on a trampoline. So the acceleration or height of jump depends on 2 things, your weight and the effort or force you put while jumping. That’s exactly what the Newton’s 2nd Law states: The acceleration of an object depends on its mass and the net force acting upon it.
The Third Explaining All The Bounce
When we push ourselves into the trampoline, what exactly pushes us out of it. And also why it pushes us out and above the trampoline level making us bouncing off in the air. It is simply the reactive force of the trampoline which is exactly equal to the amount of force you apply to it. So if you jump softly you bounce soft and if you jump hard you bounce hard. So hence Newton’s 3rd Law: For every action, there is an equal and opposite reaction.
Illustration Of The 3rd By Hooke’s Law
Hooke’s law comes into action whenever there is an elastic object in the picture. In this case, a trampoline has a fabric that is attached to its stand or frame with springs. The Law states that: the force needed to extend a spring is proportional to the length of the extension. It simply defines that the force you will apply to jump on the trampoline will be proportional to the toughness of the spring. When Newton’s law and Hooke’s law interact what happens? The spring gets stretched relative to the force and then exerts an equal force to bounce you off the trampoline.
So that’s how and why you bounce on a trampoline!