The basic formula of force can be derived from Newton’s three laws of motion. The formula for force is :
Force = mass * acceleration
Since forces are of different types, the formula of force will differ slightly according to the specific case. However, the general expression of the formula of force will not change. Force is always directly proportional to the acceleration and mass of the object. The SI unit of force will remain the same in all these cases, which is Newton.
The formula for gravitational force:
Where F is the gravitational force between two bodies, M1 and M2 are the mass of the 2 objects, r is the distance between the objects, and G is the gravitational constant. The value of the gravitational constant is 6.674 30 x 10-11Â m3Â kg-1Â s-2.
The formula for normal force:
The normal force is a type of action-reaction force. It is always equal to the force applied by the body in the perpendicular direction at the point of contact. On earth, in a non-inclined condition, the formula for normal force will be:
F= m*g [Where g is the acceleration due to gravity, whose value on earth is 9.8 m/s2]
F= m*g cosθ, [where θ is the angle of incline, in case of an inclined surface]
The formula for air resistance:
The air resistance, or drag, is a type of friction that depends on the velocity of the object the area of contact, and the air density. So, the formula of drag force is:
The formula for tension force:
Tension can be considered like an action-reaction force developed in a string or rope. Its value is always equal to the force by which it is pulled. It reaches a maximum at the fracture point beyond which it breaks in an ideal case. It is a self-adjusting force.
The formula for spring force:
Spring force is created due to the elongation or compression of a spring. So, the value of the spring force is directly proportional to the extent to which the spring is compressed or elongated. The formula for spring force is:
Where F is the spring force, k is the spring constant and Δx is the spring constant
The formula for frictional force:
The frictional force is directly proportional to the normal force acting at the plane of contact of two bodies. You can read more in our post on factors affecting friction. The formula for friction is given by:
where f is the frictional force, μ is the coefficient of friction and N is the normal force at the point of contact.
The formula for electrostatic force
The electrostatic force is a non-contact force that operates between two charged bodies separated by a distance. Coulomb’s law gives us the expression for the force between two charged bodies. Coulomb’s law states that the electrostatic force between two bodies is directly proportional to the magnitude of charges and inversely proportional to the square of the separating distance between them.
Where Q1 and Q2 are the values of the charges and r is the distance between the charges. K is the Coulomb’s law constant and its value is equal to 9.0 x (109 N*m2)/C2.
The formula for centrifugal force
Centrifugal force always tries to push the object away from the center in a circular motion. The formula for centrifugal force is given by the equation:
Where F is the centrifugal force, m is the mass of the object and v is the velocity of the moving object.
The formula for centripetal force
centripetal force always tries to pull the object towards the center in a circular motion. The formula for centripetal force is similar to centrifugal force but opposite in direction.
