{"id":351,"date":"2026-06-28T20:05:56","date_gmt":"2026-06-28T20:05:56","guid":{"rendered":"https:\/\/physicsfundamentalsinfo.com\/blog\/?p=351"},"modified":"2026-07-13T23:29:59","modified_gmt":"2026-07-13T23:29:59","slug":"types-of-forces","status":"publish","type":"post","link":"https:\/\/physicsfundamentalsinfo.com\/blog\/mechanics\/types-of-forces\/","title":{"rendered":"What Are the Types of Forces in Physics?"},"content":{"rendered":"\n
Definition<\/div>

\nTypes of forces in physics fall into two broad groups: contact forces, which act only when objects physically touch \u2014 friction, tension, the normal force, applied force, spring force, drag and buoyancy \u2014 and non-contact (field) forces, which act across a distance: gravity, electromagnetism, and the strong and weak nuclear forces. Force is measured in newtons (N) and obeys F = ma.\n<\/p><\/div>\n

Right now, without lifting a finger, you are caught in a tug-of-war. Gravity drags you down into your seat, and the chair pushes back up with just enough force to hold you in place. Pick up your phone and your fingertips grip it through friction, your arm hauls it up against its weight, and the charging cable hangs under its own tension.<\/p>\n

Forces are the hidden hands behind every push, pull, stretch and squeeze in the universe. The good news? Physics sorts that bewildering variety into a surprisingly short list. Learn the list, and the whole of mechanics starts to click into place.<\/p>\n

What Is a Force in Physics?<\/h2>\n

Strip away the jargon and a force is simply a push or a pull. It is what one object does to another when it speeds it up, slows it down, changes its direction, or bends and squashes it out of shape.<\/p>\n

More precisely, a force is any influence that can change an object’s motion or shape. Because a force has both a size and a direction, it is a vector<\/strong> \u2014 “10 newtons” is only half the story until you also say which way<\/em>.<\/p>\n

The unit is the newton (N)<\/strong>, named after Isaac Newton. To get a feel for it, a medium apple resting in your palm pushes down with roughly one newton. Hold ten apples and you are feeling about ten.<\/p>\n

One idea underlies everything that follows: a single object usually has several forces acting on it at once. What actually happens to it depends not on any one force, but on how they all add up.<\/p>\n

The Two Main Types of Forces: Contact vs Non-Contact<\/h2>\n

The cleanest way to sort the types of forces is by one question: do the objects have to be touching?<\/p>\n

Contact forces<\/strong> need physical contact. Friction, tension, the normal force, an applied push, a spring’s pull and air resistance all switch off the instant the surfaces separate.<\/p>\n

Non-contact forces<\/strong> \u2014 also called field forces or “action-at-a-distance” forces \u2014 reach across empty space. Gravity holds the Moon in orbit across 384,000 km of vacuum, and a magnet tugs a paperclip before they ever meet.<\/p>\n\n <\/rect>\n <\/rect>\n FORCES<\/text>\n \n <\/line>\n <\/line>\n <\/line>\n <\/line>\n <\/g>\n <\/rect>\n Contact forces<\/text>\n objects must physically touch<\/text>\n <\/rect>\n Non-contact (field) forces<\/text>\n act across a distance<\/text>\n \n <\/rect>Applied force<\/text>\n <\/rect>Normal force<\/text>\n <\/rect>Friction<\/text>\n <\/rect>Tension<\/text>\n <\/rect>Spring (elastic) force<\/text>\n <\/rect>Air resistance \/ drag<\/text>\n <\/rect>Buoyancy (upthrust)<\/text>\n <\/g>\n \n <\/rect>Gravitational force<\/text>\n <\/rect>Electromagnetic force<\/text>\n <\/rect>Strong nuclear force<\/text>\n <\/rect>Weak nuclear force<\/text>\n <\/g>\n At the atomic scale, every contact force is electromagnetic.<\/text>\n<\/svg>\n

Figure 1: The two families of forces. Everyday contact forces (left) need touching; field forces (right) act across empty space. Remarkably, all contact forces trace back to one field force \u2014 electromagnetism.<\/em><\/p>\n

Here is a summary you can scan in seconds. Note that weight is the odd one out in everyday physics \u2014 it is the only common force that is non-contact.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
Force<\/th>\nType<\/th>\nDirection it acts<\/th>\nFormula<\/th>\nEveryday example<\/th>\n<\/tr>\n<\/thead>\n
Weight (gravity)<\/strong><\/td>\nNon-contact<\/td>\nVertically downward<\/td>\nW = mg<\/td>\nA dropped ball falling<\/td>\n<\/tr>\n
Normal force<\/strong><\/td>\nContact<\/td>\nPerpendicular to the surface<\/td>\nvaries<\/td>\nA book resting on a table<\/td>\n<\/tr>\n
Friction<\/strong><\/td>\nContact<\/td>\nOpposes relative motion<\/td>\nf = \u03bcN<\/td>\nWalking without slipping<\/td>\n<\/tr>\n
Tension<\/strong><\/td>\nContact<\/td>\nAlong a rope, pulling inward<\/td>\nvaries<\/td>\nA cable holding a lift<\/td>\n<\/tr>\n
Applied force<\/strong><\/td>\nContact<\/td>\nDirection of the push or pull<\/td>\nvaries<\/td>\nPushing a shopping trolley<\/td>\n<\/tr>\n
Spring (elastic)<\/strong><\/td>\nContact<\/td>\nOpposes the stretch or squeeze<\/td>\nF = \u2212kx<\/td>\nA stretched bungee cord<\/td>\n<\/tr>\n
Air resistance (drag)<\/strong><\/td>\nContact<\/td>\nOpposes motion through the air<\/td>\nF = \u00bd\u03c1v2<\/sup>Cd<\/sub>A<\/td>\nA skydiver slowing down<\/td>\n<\/tr>\n
Buoyancy (upthrust)<\/strong><\/td>\nContact<\/td>\nVertically upward<\/td>\nF = \u03c1Vg<\/td>\nA boat floating<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Contact Forces, One by One<\/h2>\n

Contact forces are the ones you meet every waking second. Let’s walk through the headline types.<\/p>\n

Applied force<\/h3>\n

This is the most intuitive force of all: a direct push or pull from a person, a motor, or another object. Shoving a door, kicking a ball, towing a caravan \u2014 each is an applied force acting in the direction you push.<\/p>\n

The normal force<\/h3>\n

Every surface you press on presses back. The normal force is that support push, and it always points perpendicular<\/em> (“normal”) to the surface \u2014 straight up from a flat floor, but at an angle from a ramp. It is the reason you don’t sink through your chair.<\/p>\n

Friction<\/h3>\n

Friction resists sliding wherever two surfaces meet. It comes in two flavours: static friction<\/strong>, which holds a stationary object in place up to a limit, and kinetic friction<\/strong>, which drags on an object already moving.<\/p>\n

f = \u03bcN<\/div>\n