Q. 144.3( 14 Votes )

What is kinetic energy? Derive an equation for the kinetic energy of a body of mass ‘m’ moving at a speed ‘v’.

Answer :

A body in motion posses kinetic energy

Let us assume that an object of mass(m) is at rest on a smooth horizontal plane as shown above . Let it be displaced through a distance ‘s’ from the point A to B by force(F) acting upon it in the direction of the displacement. In the horizontal direction the net force is equal to the applied force F.

The work done on the object by the net force W = Fxs ---(i)

Let the work done on the object cause a change in its velocity from ‘u’ to ‘v’ and the acceleration produced be ‘a’

The relation between initial velocity u, final velocity v, acceleration ‘a’ and displacement ‘s’ is given from the equation of motion as


By newton’s second law of motion

F = m x a --(iii)

From equation (i), (ii) (iii) ,we have

Note:- A Special case is when the object is initially at rest i.e u = 0 ,In that particular case ,Formula of Kinetic Energy comes to be K.E = .

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Conservation of Mass-Energy41 mins
Cell Organelles of Energy Metabolism49 mins
Champ Quiz | 2-Dimension( Coordinate geometry )36 mins
Matter and Its Classification34 mins
NCERT | Angle Sum Property44 mins
India – size and location34 mins
Rest and Motion59 mins
Cell Appendages and Transport60 mins
Speed and Velocity59 mins
Wren and Martin | Grammar44 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses