Can anybody give real life situations of linear and quadratic equations?

Question

Can anybody give real life situations of linear and quadratic equations?

Answer 1

Geometry, working out the number of symmetries an object has or just seeing how much 3 apples at 50p each and 6 bananas at 45p each will cost in total.

Answer 2

Linear:  converting from fahrenheit to centigrade is a linear function; if you know two points (F=32, C=0), (F=212, C=100) you can derive the formula in general.

Quadratic:  the path of thrown or dropped objects is quadratic with respect to time.