Question

Can the kinetic energy of an object be negative? Can the potential energy of an object be negative? Can a potential energy function be defined for the force of friction?

Answer 1

Answer:

Kinetic energy cannot be negative

potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force

Explanation:

Kinetic energy of an object is given by the formula

$KE = \frac{1}{2}mv^2$

here we know that

m = mass of object that can not be negative

v = speed of the object and since its square is given here so it can not be negative

so Kinetic energy is always positive

potential energy is given as the energy due to the virtue of the position of object

so it is

$\Delta U = -\int F.dr$

so potential energy is a reference dependent quantity and it can be positive as well as negative both

Since potential energy is defined only for conservative force so it can not be found for friction force