What are some inventions that were solutions to problems?

What is the ideal water pressure of a home? Is a template for creating a set of objects having common characteristics and behaviour? Compare and constast fuses and circuit breakers? What objects exhibit two dimensional motion? Will voltage or current be higher in a circuit during short circuit? How can you reduce crawling in 3 phase induction motors? Using a screwdriver with a straight arm requires? Is it true that a derived class inherits all the members of its base class? Why vb is called event driven programing language? Who invented cylinder? What are the primary and secondary telecom cable color codes? Which material used to make a lathe bed? What is fit in mechanical engineering? Calculate pump efficiency for submersible pump? What do miners use? When was the first propeller plane made? Ring final circuits in domestic properties usually require a protective device which is rated at? What materials are needed to build a barrel vault ceiling? What is the function of the dot operator? Even number program?