Find the mass of the object in kilograms, because kilogram is the standard unit of mass. The mass of the object should be given in a problem requiring you to find the force. Find the acceleration of the object in meters per second squared, because m/s^2 is the standard unit of acceleration. Convert all measurements to the correct SI units before proceeding. If you are not given the acceleration but the object's initial and final velocity over time instead, use the formula for acceleration, which is final velocity minus initial velocity divided by the time.
Write down the formula f = m * a, and enter the known measurements in the formula.
Multiply the mass and acceleration. The final answer should be in the correct SI unit of force, which is indicated by N for newton. 1 newton is equal to 1 kg x 1 m/s^2. If the mass of an object is 6 kilograms and its acceleration is 3 m/s^2 , multiply 6 kilograms by 3 m/s^2 to get 18 N.