Question

People playing a basketball game in a gymnasium make up a closed system

with 17,125 J of energy. At the beginning of the game the system has 16,250

J of ME, and at the end it has 1,135 J of ME. How much of the total energy

was transformed into thermal energy during the game?

Answer 1

15,115 J of the total energy is transformed to thermal energy during the game.

Step-by-step explanation:

From the law of conservation of energy, initial energy of the closed system E = final energy of closed system , E'

E = E'.

Let ME = initial mechanical energy of the system = 16,250 J and U = initial internal energy of the system and ME' = Final mechanical energy of the system = 1,135 J and U' = Final internal energy of the system.

So E = ME + U and E' = ME' + U'

We now find U and U'

Substituting E, ME, E' and ME' into the equations, we have

E = ME + U

17,125 J = 16,250 J + U

U = 17,125 J - 16,250 J

U = 875 J

E' = ME' + U'

17,125 J = 1,135 J + U'

U' = 17,125 J - 1,135 J

U' = 15,990 J.

The change in internal energy is also the change in thermal energy. So,

ΔU = U' - U

ΔU = 15,990 J - 875 J

ΔU = 15,115 J

So 15,115 J of the total energy is transformed to thermal energy during the game.