Landing is one of the most hazardous parts of any flight. Spacecraft try a number of ways to land safely, either on the Earth at the end of a manned mission, or on other worlds as part of robotic exploration missions. A good understanding of forces is essential to design and construct a safe landing system that protects both your spacecraft and its precious payload.
Long ago, in the island of Sri Lanka… There was a rich man who owned, almost all the land that is now called Sri Lanka. And he parcelled out the land into small pieces which he rented to the villagers around the island. And in return for the land, they paid him rent. And these villagers scraped a very poor living off the land. There was just enough land, to grow just enough food, to feed their family and pay their rent.