Question

Derive an expression for kinetic energy possessed by an object of mass m moving with velocity v. also state si unit of kinetic energy.

Answer 1

consider an object mass m moving with a uniform speed u. let it displaced a distance s. we know that work done is W=F×S. work done by the object will cause change in velocity . let it's velocity change to u to v. let the acc. be a.

from third equation of motion we get:
s=v2 - u2÷2a.

we also know that f = m×a. so we get:
W=1/2m(v2-u2).

If the object is starting from it's stationary position then u=0:

W=1/2mv2.
work done is equal to the change in kinetic energy of an object.
Kinetic energy=1/2mv2.
Kinetic energy's S.I unit is joule.
since work done is equal to kinetic energy and si unit of work done is joules.
hope it helps

Answer 2

kinetic energy = 1/2mv^2
The SI unit is kgms-2