A body weighing 8 kg is at a height of 2.5 m. Does the body have kinetic energy if its mechanical energy is 300 J?

Absolutely any object has potential energy, which can be determined using the following formula:

En = m * g * H,

Where:

Ep is the potential energy of the object;
m is the mass of the object (according to the condition of the problem, 8 kg);
g – acceleration due to gravity (constant value is 9.8 m / s ^ 2);
H is the height of the object above the Earth’s surface (according to the problem statement, 2.5 m).
If we substitute all known values ​​into the formula, we get:

Ep = 8 * 9.8 * 2.5.

En = 196 J.

Determination of the value of kinetic energy
At its core, mechanical energy is the sum of potential and kinetic energy.

Em = En + Ek.

In this case, since the mechanical energy is 300 J, and the potential energy is 196 J, we can conclude that the body has kinetic energy, which will be equal to the difference between the mechanical and potential energy.

In this case, we get:

Ek = Em – En.

Ek = 300 – 196 = 104 J.

Answer:

The body has kinetic energy. It is 104 J.