What’s the secret to pulling a tablecloth out from under plates and a full table setting? Speed!The principle of inertia states that an object at rest one that isn’t moving, like the plates stays at rest unless another force acts on that object.
In this case, the plates stay at rest because the force of you pulling down on the tablecloth isn’t enough to move them.The principle of inertia also says that if an object is moving, it will keep moving unless another force acts on that object.
Imagine you’re in a car – you and the car are both moving. If the car slows down gradually, you slow down too. The friction of your body against the seat and other forces combine to help you slow down.
If the car stops suddenly, inertia will keep you moving forward. This is why you need to wear a seatbelt. Your seatbelt prevents you from moving forward too far when a car stops suddenly.