Force is the total impact of one object on another.
Pressure is the ratio of force to area over which it is applied.
A force is defined as a push or a pull that makes an object change its state of motion or direction. For example, when a golf player tees off with his club, he applies 'force' on the ball, with the result, the ball, which was static, goes into a state of motion and remains in motion till it is stopped by friction and force of gravity. A force can either cause a moving body to stop, make it move faster, or change its direction.
Force is a vector quantity which means it has a magnitude as well as direction. Force is dependent upon the mass of the body which accelerates upon application of force and the three are related as per following equation (Newton’s second law of motion)
Force= Mass x Acceleration
The unit of force is the NEWTON. One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared.
Pressure is a physical quantity that is a force spread over a certain area. In other words, pressure is force per unit area. If you take the amount of force being applied on a body, divide it with the area of contact, you will arrive at the pressure being applied on the body.
Pressure = force/area
This means that same force, when applied on a smaller area will produce greater pressure than when applied to a larger surface area. For example, the force I exert on the floor when standing on both feet is the same as the force I exert on the floor even while standing on one foot. However, when standing on one foot I put twice the pressure on the floor.
Pressure has no direction and has only magnitude and so is a scalar quantity. and .
Units of pressure are Pascal (P) or Newton per square meter, pounds per square inch, kilograms per square centimeter, etc.