Added mass

Okay kiddo, so added mass is like when you get into a swimming pool and the water level goes up, because you are adding your mass to the pool. When an object moves through water (or any fluid), it also adds its own mass to the fluid around it. This is called added mass.

So let me explain it better. When you move through a fluid, like water, the fluid has to move out of your way. And when it moves, it creates a pressure or a force on you, which slows you down. The amount of force that the fluid puts on you depends on your mass, your velocity, and the viscosity of the fluid. But when you move really fast, the fluid can't move out of your way quickly enough, and it piles up in front of you, like a wave.

This wave of fluid in front of you increases the effective mass of your object, which is called the added mass. So, if you were trying to push a ball through water, the added mass would make it harder to move the ball, because it would feel like the ball has more mass than it actually does. This effect is important to know if you are designing boats, submarines, or airplanes that move through fluids.

So, to put it simply, added mass is like carrying heavy bags while trying to move fast. Even if you are not carrying any bags, the wind or the water can create a force that slows you down, making you feel like you are carrying extra weight. That's added mass!