A sling cart is a special kind of cart that helps move heavy objects from one place to another. The cart has two big wheels and a platform in the middle where you put the heavy object. There are also two long straps attached to the sides of the cart. These straps go under the heavy object and over the top to create a sling.
Now imagine you have a super heavy box that you need to move. You can't just pick it up and carry it to where you want it to go. That's where the sling cart comes in! You put the heavy box on the platform of the cart, then you take the two straps and put them under the box. Then you pull the straps up and over the top of the box, so it's like the box is now wearing a seatbelt.
Next, you hold onto the straps and pull the cart along with you to where you need to go. The straps help support the weight of the box so you don't have to lift it all by yourself. This makes it easier and safer to move heavy things, especially if you're not very strong. And that's what a sling cart is!