The so-called kinetic energy, simply put, refers to the body because of motion and energy. number is tantamount to (1/2) Mv^2. Kinetic energy is one kind of energy, its unit under the International system of units is joule (J), short for joule. Note that kinetic energy (and the work that corresponds to it) both are Scalar quantity, that is, magnitude and no direction. When summing, it only calculates the number sum, which does not satisfy the vector (called vector in math) in addition to parallelogram rule.

Do work：W_T=1/2(mv²)-1/2mv²

here:

W_T = Total work

m = Quality ,

v_i =Inception speed

v_f =finally speed 。