Mechanics Questions with Step-by-Step Solutions

Mechanics problems are easier once the physical model is chosen. Draw the system, list forces or conserved quantities, pick a positive direction, and only then choose equations. The worked questions below show when kinematics, Newton's laws, energy, or momentum gives the shortest valid path.

Check dimensions on every equation and inspect the sign of the final result. A negative velocity may be physically correct, while a negative mass or time is not. Free-body diagrams should contain forces acting on the chosen object, not velocity or forces the object exerts on something else.

Before reading a solution, name the system and governing principle in one line. Compare that line with the worked method, locate the first different modeling choice, and redraw the diagram before attempting another problem.