a loudspeaker converts electrical energy into the kinetic energy of the speaker. this kinetic energy is…

a loudspeaker converts electrical energy into the kinetic energy of the speaker. this kinetic energy is transferred to air, and the motion of the air is the sound that people hear. how much thermal energy is put out by the speaker? 5 j 15 j 80 j 100 j sound energy 80 j electrical energy 100 j thermal energy? j friction 5 j

a loudspeaker converts electrical energy into the kinetic energy of the speaker. this kinetic energy is transferred to air, and the motion of the air is the sound that people hear. how much thermal energy is put out by the speaker? 5 j 15 j 80 j 100 j sound energy 80 j electrical energy 100 j thermal energy? j friction 5 j

Answer

Explanation:

Step1: Apply energy - conservation principle

The total electrical energy input is converted into sound energy, thermal energy and energy lost to friction. Let the electrical energy be $E_{e}=100\ J$, sound energy be $E_{s}=80\ J$ and friction energy be $E_{f}=5\ J$, and thermal energy be $E_{t}$. According to the law of conservation of energy $E_{e}=E_{s}+E_{t}+E_{f}$.

Step2: Solve for thermal energy

We can re - arrange the formula to find $E_{t}$: $E_{t}=E_{e}-E_{s}-E_{f}$. Substitute the given values: $E_{t}=100 - 80-5$. $E_{t}=15\ J$

Answer:

15 J