KE=1/2 m v^2
KE= .5 x 2kg x 15m/s to the 2nd power
KE=225 km/s
The law of conservation of energy<span>, a fundamental concept of physics, states that the total amount of </span>energy<span> remains constant in an isolated system. It implies that </span>energy<span> can neither be created nor destroyed, but can be change from one form to another.</span>
<span>NaCH is not an element, it is a compound. An element can be found and identified on the periodic table to elements. A compound is a combination of two of more elements. NaCH is composed of three elements: Na (sodium), C (carbon) and H (hydrogen), making it a compound.</span>
An increase in voltage causes the flow of electric current to INCREASE. An increase in resistance causes the flow of electric current to DECREASE.
100% right
To solve this problem it is necessary to apply the concepts related to the Conservation of Energy, for which it is necessary that any decrease made through the potential energy, is equivalent to the gain given in the kinetic energy or vice versa.
Mathematically this can be expressed as

Since there is no final potential energy (the height is zero), and the initial potential energy is equivalent to the work done we have to






Therefore the non-conservative work was done on the boy is 1.4kJ