Work Calculator
Calculate work done by a force. Enter force, distance, and angle between force and displacement to determine work energy.
What is work in physics?
Work is the energy transferred when a force moves an object. The formula is W = F * d * cos(?), where F is force, d is displacement, and ? is the angle between force and displacement. Work is measured in Joules (J), where 1 J = 1 N*m.
Why does angle matter in work calculations?
Only the component of force in the direction of motion does work. If force is parallel to motion (?=0deg), cos(0deg)=1, so W=F*d. If perpendicular (?=90deg), cos(90deg)=0, so W=0 (no work). At other angles, cos(?) gives the effective force component.
What is positive work vs negative work?
Positive work (W>0) occurs when force aids motion (0deg=?<90deg), adding energy to the object. Negative work (W<0) occurs when force opposes motion (90deg<?=180deg), removing energy. Example: lifting = positive work, friction = negative work.
When is no work done?
No work is done when: (1) force is perpendicular to displacement (?=90deg), like centripetal force in circular motion; (2) there's no displacement (d=0), like pushing a wall that doesn't move; (3) there's no force (F=0).
What are common units for work and energy?
SI unit: Joule (J) = N*m = kg*m^2/s^2. Other units: kilojoule (kJ) = 1000 J, foot-pound (ft*lb), calorie (cal), kilocalorie (kcal or Cal), electron-volt (eV). Conversions: 1 J = 0.738 ft*lb, 1 ft*lb = 1.356 J.
How does work relate to energy?
The Work-Energy Theorem states that net work equals change in kinetic energy: W_net = DeltaKE = ?m(v_f^2 - v_i^2). Work transfers energy between objects or converts it between forms (kinetic, potential, thermal). Energy conservation: work done = energy transferred.
What is the difference between work and power?
Work is total energy transferred (measured in Joules). Power is the rate of doing work: P = W/t (measured in Watts). Example: lifting 100 kg 2 m does ~1960 J of work whether it takes 1 second (1960 W power) or 10 seconds (196 W power).
Can work be done by multiple forces?
Yes. Calculate work for each force separately, then add algebraically (considering signs). Net work = W_1 + W_2 + ... Total work equals work done by net force: W_net = F_net * d * cos(?). Example: car moving with engine force (+) and friction (-).
What are real-world examples of work calculations?
Examples: lifting objects (W = mgh), pulling a sled (W = F*d*cos(?)), compressing a spring (W = ?kx^2), braking a car (negative work by friction), pumping water uphill, loading cargo, and construction equipment operations.
How do I calculate work done against gravity?
For vertical lifting: W = mgh, where m is mass, g is gravitational acceleration (9.8 m/s^2), and h is height. This simplifies W = F*d with F = mg (weight) and d = h. Example: lifting 10 kg up 2 m requires W = 10*9.8*2 = 196 J.
What is work done by friction?
Friction always opposes motion, so ? = 180deg and cos(180deg) = -1. Work by friction: W = -f*d (always negative), where f is friction force. This removes kinetic energy, converting it to heat. Example: friction f=50 N over d=10 m does W = -500 J.
How do I convert between Joules and foot-pounds?
Conversions: 1 J = 0.737562 ft*lb, and 1 ft*lb = 1.35582 J. To convert: multiply Joules by 0.7376 to get ft*lb, or multiply ft*lb by 1.356 to get Joules. These units are common in imperial/metric engineering contexts.