Now, after putting the value of a, we have d ( mass x acceleration x displacement)Īs per the third equation of motion, the acceleration is given by So, after putting the value of f, we have For example, a body of mass 'm' is pushed by applying force 'f' and it covers a distance 'd' on a surface, this the work done on the object makes it move and due to movement it possesses kinetic energy, so work done in this case, is equal to kinetic energy or can be used to derive kinetic energy equation. The kinetic energy equation or formula can be derived from the work done (w) by a force (f) on an object. The kinetic energy of a moving object remains unchanged unless the speed or mass of the object is changed.ĭeriving Kinetic Energy Equation or Formula.So, a car moving to the north with a speed of 50 kmph will have the same kinetic energy as a car moving in the south direction or any other direction with the same speed. Kinetic energy is a scalar quantity, not a vector.Although the value of velocity can be positive or negative, the value of the square of velocity is always positive. The value of kinetic energy is always positive.For example, a 2 kg object moving at a speed of 1 m/s will have a kinetic energy of 1 joule.Īs per the centimetre-gram-second system, the unit of energy is the erg, 10 -7 joule, which is equal to the kinetic energy of a mosquito flying in the air. It is also a type of energy and the unit of energy in the metre-kilogram-second system is the joule. The SI unit of kinetic energy is the joule (J), which is equal to 1 kg.m 2.s- 2. For example, if a moving car collides with a stationary object then some of the kinetic energy of the car gets transferred to the object or transformed into another type of energy. Further, it can be transformed into other types of energy. Kinetic energy can be transferred from one object to the other or between objects. So, a large truck will have more kinetic energy than a small truck and will cause more damage when it hits something. For example, a truck moving at 50 kmph will have four times the kinetic energy of the same truck moving at 25 kmph. For example, a moving truck at twice the speed will have four times the kinetic energy. So, if we double the mass, the energy will get doubled and if we double the velocity, it will be four times the previous value. The above formula also shows that K.E is directly proportional to the mass and square of the velocity of the object. The above formula tells the amount of work a moving object can do as a result of its motion. Kinetic Energy is a scalar quantity so it does not depend on the direction and thus its value will always be positive.Īs we know energy is the capacity to do work and kinetic energy is also a type of energy, so the above formula of kinetic energy is the expression of the fact that a moving object has kinetic energy that can do work on anything it hits. So, the kinetic energy of an object can be calculated as half its mass times the square of its velocity (v). The kinetic energy of an object of mass 'm' moving with velocity 'v' is given by The formula of kinetic energy shows the relation of energy with mass (m) and velocity (v).

Further, the kinetic energy of an object is due to the net work done on it as no object can move and cover the distance without applying a force on it. So, every moving object around us possesses kinetic energy. In simple words, we can say that it is the energy of motion. The energy possessed by an object due to its motion in any direction (horizontal or vertical) is known as kinetic energy.

Energy of motion