ya its an common doubt for many people..in my view mechanical engineer differs from mechanic in many aspects..mechanical engineer and mechanic both have subject but mecahnic dont consider many of the technical aspects while designining an new machine or some thing else
Mechanics know the knowledge of how to fix machinery such as cars. They would generally have a apprenticeship with a company and/or gain a qualification, in the UK this is generally at a college.
Mechanical Engineers can vary widely, some may be responsible for the design of a product, others for the manufacturing or testing. They need to know mathematics and physics to ensure the product meets its specifications, and as such would go to a University, or High School in the USA, to gain a Degree or Major in Mechanical Engineering.
Subjects may include:
- Thermofluid mechanics--mechanics, such as flow (of liquids and gases) etc.
- Solid mechanics--bending in beams, Forces & Moments, gears, etc.
- Finite Element Analysis(FEA)--forces and stresses in components on a small-scale, understanding how to use FEA programmes.
- Engineering Management--understanding some business methods and manufacturing methods for successful production of a product.
- Materials & Manufacturing
List above isn't meant to be exhaustive and therefore includes only a few subjects that one may encounter at a University or High School. Courses may vary depending on where they are taken and even then you may only learn 10% of what you need to know to when you graduate.