Question

using the law of conservation of energy obtain the expression for the escape velocity​

Answer 1

Answer:

It is the minimum Velocity with which a body should be projected from the surface of the planet so as to reach infinity .

DERIVATION :

If a body of mass m is projected with velocity Ve from surface of planet mass M and Radius R , So by law of Conservation of Mechanical Energy

KE + PE at surface of planet = KE + PE at infinity .

1/2 ×m×v^2 + ( - GMm/R ) = 0 + 0

1/2 m×v^2 = GMm/R

Or

Ve = √GM/√R

we know that GM = gR^2

so,,

here r = R only .

If we put value of R and g of Earth we get Ve = 11.2 Km/s ( approx ) .

HOPE IT HELPS U ^_^

Answer 2

Explanation:

According to law of conservation of energy,

potential energy + kinetic energy = always constant

For example,

suppose the boy standing on a building whose height is 40 m.He spend 40 joule energy to push a ball .The potential energy of ball is 29 joule.

Then,

Potential. + kinetic .= 40 joule

29 j + kinetic. = 40 joule

kinetic = 40-29=11 joule

law of conservation of energy,

potent. + kinet. = constant

29 +11 = 40

40=40

Since the law of conservation is true and it also states the energy cnnot be destroyed or cannot be created.

Hope this will helped you.

Thanks