Newton’s Second Law Of Motion
| Newton’s second law of motion states as follows:
The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts. Before continuing, let’s see what momentum is The momentum of a body is defined as the product of its mass and its velocity. That is, the momentum of a body is equal to mv. With mass in kg and velocity in m/s, the Standard International (SI) unit of momentum is kgm/s. Notice that the greater the momentum of a body, the greater the force it will exert on another body. Now back to Newton’s second law of motion: Mathematically, Newton’s second law of motion can be expressed as Force α change in momentum/time F α (mv-mu)/t where F represents a force on a body of mass m causing it to change its velocity from u (initial velocity) to v (final velocity) over a time t. Simplifying further, we have F α m(v-u)/t (v-u)/t is the rate of change of velocity, and is same as acceleration, a. Therefore, F α ma, and F = kma, where k is the force constant. The SI unit of force is the Newton (N). It is the force which acts on a body of 1kg, making it to accelerate by 1m/s2. Therefore, when F is in Newtons, m in kg and a in m/s2, F = ma Or F = m(v-u)/t See calculations of force based on Newton’s second law of motion here. |