How to Calculate Acceleration From Force

You can use Newton's Second Law of Motion to calculate the acceleration of an object if you know the force applied to it and its mass. Newton's Second Law states that an object will accelerate in the direction that the net force (sum of all forces acting on the object) is applied. The equation to calculate acceleration is force divided by mass, or a = f/m.

• 1

  Draw arrows projecting from the object in the direction of the forces acting on the object. For example, if a person is pushing the object to the left with 10 newtons of force, draw an arrow pointing to the left. Label each arrow with the amount of force in newtons that is being applied in that direction.

• 2

  Find the net force acting on the object using vector addition. For example, if there was a force of 10 N (newtons), another force of 15 N pushing to the right and a force of 12 N pushing to the left, you would add 10 and 15, then subtract 12 to find the net force: 13 N pushing to the right.

• 3

  Calculate the force of kinetic friction if there is friction between the object and the surface. The force of kinetic friction always pushes in the opposite direction as the net force. The equation for kinetic friction is Friction = μ*mg, where μ is the constant of friction (stated in the problem), m is the mass of the object, and g is equal to 9.8. Subtract the force of friction from your net force.

• 4

  Calculate the acceleration of the object using Newton's Second Law. Divide the value you obtained in Step 3 by the mass of the object (in kilograms). The result is the acceleration of the object in meters per second squared. The direction of the acceleration is the same as the direction of the net force.