| Some Common Forces | |||
| name/symbols | when/where | direction | |
|---|---|---|---|
| weight | W, Fg | due to gravity | down |
| normal | N, Fn | surfaces in contact | normal to surface |
| friction | f, Ff | surfaces in contact | tangent to surface |
| tension | T, Ft | strings, ropes, cables, etc | along the axis |
| elasticity | Fe, Fs | springs, rubber bands, etc. | along the axis |
| buoyancy | B, Fb | immersed in a fluid | up |
| drag | R, D, Fd | moving through a fluid | opposite velocity of object |
| lift | L, Fl | moving through a fluid | perpendicular to flow |
| thrust | T, Ft | pushing a fluid | opposite velocity of fluid |