# Can a person have zero mechanical energy?

## Can a person have zero mechanical energy?

It is given that, momentum of the body is zero, it means the velocity of the body is zero. But Mechanical energy is the sum of kinetic energy and potential energy. So the kinetic energy of a body is equal to zero equals zero. So, even if the momentum of the body is zero, it may have mechanical energy.

## Is energy always positive?

Since kinetic energy is based on motion, it is always a positive value. If it is not in motion, the kinetic energy of that object is zero. Kinetic energy can never be a negative value.

Is internal energy always positive?

The internal energy has the symbol U. Q is positive if heat is added to the system, and negative if heat is removed; W is positive if work is done by the system, and negative if work is done on the system.

### How come the total energy is greater than the potential energy?

That means that an electron at a large distance from the nucleus, without additional energy, cannot remain there. In other words, the electron is bound to the nucleus. That is the meaning of the absolute value of potential energy being greater than the total energy, and greater than the kinetic energy.

### What is classical turning point?

The classical turning point is that value of the x-coordinate at which the potential energy is equal to the total energy, and therefore classically the system must reverse its direction of motion.

Can total energy be less than potential?

From a classical point of view, the movement of the object is restricted to the zone where total energy is less than potential energy. The other regions are “forbidden” in the sense that, within those zones, the kinetic energy is less tan zero and it would lead to an imaginary speed.

#### Why is kinetic energy lower than potential energy?

For example, an object which is falling, but has not yet reached the ground has kinetic energy because it is moving downwards, and potential energy because it is able to move downwards even further than it already has. As an object falls its potential energy decreases, while its kinetic energy increases.