Question

Define and derive formula for potential and kinetic energy

Answer 1

Dear Student,
•Kinetic energy -
The energy possessed by virtua of its motion is said to be kinetic energy. SI unit of kinetic energy is joule (J).
K E = 1/2mv²

Derivation : we know that

W = f x s

but f = ma

W = mas......-> Eqⁿ 1

By 3rd Eqⁿ of motion

v² = u² + 2as

at rest u=0

v² = 2as

as = 1/2 v²

Putting in Eqⁿ 1

W = 1/2 mv²

Since work done is stored in kinetic energy.

so, K E = 1/2 mv²

• Potential Energy -
The energy possessed by virtua of its position is said to be potential energy. SI unit of potential energy is joule (J).
P E = mgh

Derivation: we know that

W = f x s ....Eqⁿ 1

when the object of mass m is lifted at a height h then,

F = mg and

s = h

then Eqⁿ 1 becomes

W = mgh

Since work done = P E

so, P E = mgh

Regards