ENGINEERING MECHANICS

CONCEPTS OF FORCE AND FORCE SYSTEM                                 ©subhankar_karmakar

CONCEPTS OF FORCE AND FORCE SYSTEM

               To understand force one has to understand Energy. Energy is the transferable physical quantity of an object which has the capacity to do work. Energy can be transferred from one place to another place, or from one object to another object.



               Force is the physical quantity which when acts on a body, may do some work on the body by displacing from a certain point in the space to another point in the space. When a body gets displaced due to the application of force, some work has been done on the object. So work done on a body is basically nothing but putting some more energy on the body.



               Any kind of displacement of an object is called a change in position and it is a universal truth that to go through any kind of change in position, an object needs some time interval, the process of changing position involves time, hence we can say an amount of ∆x change in position it needs ∆t amount of time. Hence, we can get a rate of change of position with respect to time.



               If in (∆t) time the body travels a distance (∆x) than,
in unit time the body travels a distance (∆x/∆t) and it is known as average velocity.



               When the time interval ∆t is very small, then the ratio of (∆x/∆t) is represented by differential operator and then it is called instantaneous velocity, V=dx/dt



               An heavier object needs more energy to attain the same velocity of that of a lighter object. It has been observed that body at a higher motion needs more energy to change velocity incrementally. Suppose we have two identical object A and B, while the velocity of A is (u), the velocity of B is larger at (v), now if we try to increase the velocity of both the body by a amount ∆v, then the body with the higher motion would need more energy per unit change in velocity.