Force, Work and Power Calculator (F = m·a, W = F·d, P = W/t)

Force is a physical quantity that causes a change in the state of motion or shape of a body. The SI unit of force is the newton (N). Newton's Second Law states F = m × a, where m is mass in kilograms and a is acceleration in m/s². A force of 1 N gives a body of mass 1 kg an acceleration of 1 m/s².

Use the formula F = m × a. Example: a car of mass 1000 kg accelerating at 2 m/s² requires a force F = 1000 × 2 = 2000 N. Select the 'Calculate force' mode, enter the mass and acceleration, and the calculator returns the force in newtons.

Mechanical work W (measured in joules, J) is the energy transferred when a body moves under the action of a force. The formula is W = F × d, where F is force (N) and d is the displacement in the direction of the force (m). Example: pushing a wardrobe with 200 N over 3 m does W = 200 × 3 = 600 J of work.

Use the formula W = F × d. Example: lifting a weight of 50 N through a height of 2 m gives W = 50 × 2 = 100 J. The calculator returns the result in joules (J) and kilojoules (kJ). Note: work is zero when the force is perpendicular to the direction of motion.

Power P (measured in watts, W) is the rate at which work is done or energy is converted. The formula is P = W / t, where W is work (J) and t is time (s). Example: doing 1000 J of work in 5 s corresponds to a power of P = 1000 / 5 = 200 W.

Use the formula P = W / t. Example: an electric motor does 30,000 J of work in 60 s — its power is P = 30,000 / 60 = 500 W = 0.5 kW. The calculator automatically converts the result from watts to kilowatts.

1 kJ = 1000 J. Joules are used for smaller energies (e.g. school physics experiments), while kilojoules are used for larger ones (e.g. food energy: 1 kcal ≈ 4.184 kJ). The calculator automatically shows work in both units.

Gravitational acceleration g ≈ 9.81 m/s² is the acceleration at which objects fall freely near the Earth's surface (without air resistance). It follows from the Earth's mass and Newton's law of universal gravitation. The weight force acting on a body of mass m is F = m × g.

From F = m × a we get m = F / a. Example: if an engine generates a force of 500 N and gives an acceleration of 2 m/s², the mass of the object is m = 500 / 2 = 250 kg. Select the 'Calculate mass' mode in the calculator.

Choose a calculation mode from the dropdown list: Calculate force (F = m × a), Calculate mass (m = F / a), Calculate acceleration (a = F / m), Calculate work (W = F × d) or Calculate power (P = W / t). Enter the required values and press Calculate. The calculator returns the result in SI units and, depending on the mode, also in kilojoules or kilowatts.