Introduction to Kinetic Energy
If we look around us, many objects are constantly moving. As a child we would have been fascinated at being able to move our toys or watch a toy car pass us by. Have we ever wondered how is this possible?
The answer is kinetic energy which is described or defined as the property of a moving object or particle. It essentially depends on the object’s movement and mass. When we perform work on an object by applying net force an energy transfer takes place. This causes the object to accelerate and absorb kinetic energy. Kinds of motion caused due to kinetic energy include moving along a path from one position to another, rotating around an axis, acceleration or a combination of these and other motions.
The unit of energy is joule in the meter-kilogram-second system. Suppose we take a two-kilogram mass which approximately weighs 4.4 pounds on earth and moves at slightly more than two miles per hour - it will have one joule of kinetic energy.
In the centimeter-gram-second system, the energy system is the erg which is 10−7 joule. This is considered equivalent to a mosquito’s energy in flight. In atomic and subatomic contexts, other units of energy include the electron volt which is an even smaller unit.
Dimensional Formula and Derivation for Kinetic Energy
To arrive at the dimensional formula of kinetic energy, we use the theorem of work-energy followed by adding Newton’s second law of motion.
Thus the dimensional formula of kinetic energy can be expressed as - [M1 L2 T-2]
Where, M = Mass, L = Length and T = Time.
The Derivation is as follows:
Step 1 - Kinetic Energy or K.E. = [Mass × Velocity2] × 2-1
Step 2 - The dimensional formula of Mass is - [M1 L0 T0]
Step 3 - The dimensional formula of velocity = [M0 L1 T-1]
Next, we substitute Steps 2 and 3 in equation 1 by which we get -
K.E= [Mass × Velocity2] × 2-1
Or, K.E = [M1 L0 T0] × [M0 L1 T-1]2 = [M1 L2 T-2]
Now we consider the fact that if kinetic energy is the energy of motion, then very naturally the kinetic energy of an object is zero.
Kinetic energy is thus dimensionally represented and expressed as - [M1 L2 T-2].
FAQs on Dimensional Formula of Kinetic Energy
1. What is the Dimension Formula of Heat?
Dimensional Formula of Specific Heat Capacity
M = Mass. K = Temperature. L = Length. T = Time.
2. What are the 7 Fundamental Dimensions?
There are 7 main measurements in all. The primary dimensions (sometimes called basic) are defined as independent or fundamental dimensions from which other dimensions can be derived. The primary dimensions are: mass, volume, time, temperature, electrical current, luminosity, and matter.
3. How many Dimensions are there?
There are three dimensions of space — length, width and depth — and one dimension of time in the universe as we know it. Yet there is the chance of mind-bending, that there are even other worlds out there. The universe works with 10 dimensions according to string theory, one of the leading physics models of the last half century.
4. What is the formula of Energy?
The formula linking power and energy is: Energy = Power x Time. The unit of energy is the joule, the watt is the unit of power and the second is the unit of time.
5. What is the SI unit of Energy?
The energy / work unit SI is the joule (J), named after English physicist James Prescott Joule (1818-1889). One joule is equal to the work done by a force of one newton moving one metre of object (J = N · m).
6. What are the seven major dimensions?
The primary dimensions are also known as independent or fundamental dimensions from which the rest of the equations and formulae are derived. These fundamental dimensions are - mass, volume, time, temperature, electrical current, luminosity and matter.
7. What are the seven base units for the seven fundamental dimensions?
The seven fundamental dimensions in physics are - mass, volume, temperature, time, electrical current, matter and luminosity. For mass, the SI unit is kilogram and for time it is second. For temperature it is kelvin and for electric current, it is ampere. For luminous intensity it is candela. For matter or amount of substance, the unit of measurement is mole. For volume it is cubic meters.
8. What are the applications of kinetic energy?
The natural sciences are thus called because of their presence all around and within us. Physics is one of the fundamental natural sciences. We can see working examples of kinetic energy in various forms. In hydropower plants, the kinetic energy of moving water gets converted into mechanical energy which moves the turbines and produces electrical energy. The kinetic energy of moving air causes the blades of a windmill to rotate and eventually generate electricity. A flying airplane has high levels of kinetic energy owing to its large mass and high velocity because of which it is able to fly high. When the human body walks or runs, there is conversion of chemical energy to kinetic energy.
9. How can one prepare for physical formulae well?
As we go through each chapter of physics especially as we enter higher classes, there are many formulae that students need to memorize. However, students need to understand the concepts behind these formulae rather than just rote learning them. A deeper understanding enhances the power of the human brain to retain those formulae for a longer period of time. Hence it is best to pay proper attention to classes or ask for assistance from Vedantu’s teachers. Students can also opt to maintain a notebook where chapter-wise formulae are noted down. Regular solving of equations using these formulae also helps understand its applications and thereby memorize it. Vedantu’s revision notes can also be of huge help!
10. What is the formula and unit of energy?
The formula for Energy = Power x Time. Joule is the unit of energy while watt is the unit for power and second is the unit for time.