Formula for kinetic energy || kinetic energy formula || Derivation of kinetic energy ||

-

 Kinetic Energy of a body can be obtained either from

(i) the amount of work done in stopping the moving body, or from

(ii) the amount of work done in giving the present velocity to the body from the state of rest. 

Let us use the second method:

Suppose, m = mass of a body at rest (i.e., u=0).

                  F = Force applied on the body

                  a = acceleration produced in the body                            in the direction of force applied. 

                 v = velocity acquired by the body in                               moving through a distances. 

From, 

                v²- u² = 2 a s

                v²- 0 = 2 a s

                  a = v² / 2 a s          .... (i) 

As    F = m a          .: using eq (i) 

        F = m (v² / 2 a s) 

Work done on the body, W = force×displacement

    W = m × v² / 2 s × s

    W = 1/2 m v²

This work done on the body is a measure of kinetic energy {K•E} acquired by the body. 

Kinetic energy of body = W = 1/2 m v².

Comments

Post a Comment

Popular posts from this blog

KVS CBSE Worksheets CHAPTER 1 Electric Charges and Fields Class 12

-
Image
                      SECTION A CONCEPTUAL AND APPLICATION TYPE QUESTIONS  1 Is the force acting between two point charges q1 and q2 kept at some distance apart in air attractive or repulsive when i) q1 q2 > 0 ii) q1 q2 < 0 ? 1 (2007)  2 If the distance between two equal point charges is doubled and their individual charges are also doubled ,what would happen to the force between them ? 1(2014)  3 Do the electrostatic field lines form closed loops? 1(2014)  4 A hollow metal sphere of radius 5cm is charged such that the potential on its is 10V. What is the electric field at the center of the sphere? 1(2011)  5 What is meant by the statement that   “the electric field of a point charge has spherical symmetry whereas electric field due to an electric dipole is cylindrically symmetrical’’ ? 1(1996)  6 Why is it difficult to perform electrostatic experiments on a humid day? 1  7 The ...
Read more

Marathon

-
                  Marathon measurements  » 1 Marathon distance = " 42.2 kilometres (km)"  = "26.2 miles"  » Half Marathon distance =0.5 Marathon =         " 21.0975 kilometres " = "13.1094 miles" » 21.1 kilometres  (13.1094 mile) is as far as: It's more than 52 laps around a track or 38 CN Towers or 231 football fields. » There are six lessons to consider before you begin you journey for half or 0.5 marathon and the full or 1 marathon: 1) Do a proper training for near about 2 years and increase you running distance every day. It is a wrong, if you are deciding to run 21.1 kilometres in the first trial. Running – smart, injury-free running – is a slow build. Choose a half marathon that's six months from now and develop a plan where you're not in a rush. It take about five weeks to get a base level of fitness – essentially where five kilometres didn't kill you. After that, you can increase you runni...
Read more

Important Multiple Choice Questions of physics || Class 11 ||

-
1. A particle moves along a straight-line y= 3x + 5. Which coordinate changes at faster rate? a) X- coordinate  b) y-coordinate  c) both x and y  d) insufficient data Ans: b) y-coordinate ( Let suppose x=1,then y=8 ,x= 2 ,y = 11. So y coordinate is increasing 3 times faster as compare to X- coordinate  ) .  2. If 𝐴⃗ + 𝐵⃗⃗ = 𝐶⃗ and A+B = C then the angle between 𝐴⃗ and 𝐵⃗⃗ is- a) 0 b) π/4  c) π/2  d) π  Ans: c) π/2 3. If a unit vector is represented by 0.5𝑖− 0.8𝑗+ c k then the value of ‘c’ is- a) 1  b) √0.11  c) √0.01 d) √0.39 Ans: b) √0.11 4. Given that A = B. what is the angle between (𝐴⃗ + 𝐵⃗⃗) and (𝐴⃗ − 𝐵⃗⃗⃗⃗⃗⃗⃗⃗) =? a) 30° b) 60° c) 90° d) 180° Ans: d) 180° 5. What is the component of the (3i+4j) along (i + j)? a) ½ (i + j)  b) 3/2(i + j)  c) 5/2 (i + j)  d) 7/2 (i + j) Ans: d) 7/2 (i + j) 6. What is the value of (𝐴⃗ + 𝐵⃗⃗).( 𝐴⃗ × 𝐵⃗⃗)? a) 0  b) A²-B² c) A²+B²+2AB  d) None of these Ans...
Read more

Khelo India Program || Physical education Chapter 1 Class 11 || Changing trends and career in physical education ||

-
                        Introduction The importance of sports and fitness in one’s life is invaluable. Playing sports inculcates team spirit, develops strategic and analytical thinking, leadership skills, goal setting and risk taking. Moto of Khelo India Program is “A fit and healthy individual leads to an equally healthy society and strong nation”.  Sports is an extremely important component for the overall development of our nation or for any nation. India, in the last five years has made steady progress in the field of sports. This tremendous potential need to be show cased at a global platform. It’s time we inspire young talent, give them top notch, infrastructure and training of the highest level. We need to inculcate a strong spirit of participation in the sports that enables players to demonstrate their true potential. Only then India can  realise its dream of becoming a sports super power.  The...
Read more

Distinction between Electromagnetic Waves and Matter Waves

-
Image
  Difference   between Electromagnetic Waves and Matter Waves » Electromagnetic waves 1. Electromagnetic waves are associated with electric and magnetic fields perpendicular to each other and to the direction of propagation of radiation. 2. Electromagnetic waves can be radiated into space or emitted. 3. They do not require any medium for propagation i.e., these waves can pass through vacuum. 4. All electromagnetic waves travel with the same velocity.  5. The velocity of all electromagnetic waves is equal to that of light (3 x 108 m/s). 6. The wavelengths of electromagnetic radiation are much large .   » Matter waves 1. Matter waves may not be associated with electric and magnetic fields. 2. Matter waves are neither radiated into space nor emitted by the particles. These are simply associated with the particles 3. They require medium for propagation i.e., these waves cannot pass through vacuum. 4. Matter waves travel with different vel...
Read more