Question

which equation correctly relates mechanical energy, thermal energy, and total energy when there is friction present in a system?
a. $e_{total}=me - e_{thermal}$
b. $e_{total}=me\times e_{thermal}$
c. $e_{total}=e_{thermal}-me$
d. $e_{total}=me + e_{thermal}$

Explanation:

Step1: Recall energy - conservation principle

In a system with friction, mechanical energy is converted into thermal energy due to frictional forces. The total energy of the system is the sum of all forms of energy present.

Step2: Identify the correct relationship

The total energy $E_{total}$ of the system is the sum of mechanical energy (ME) and thermal energy ($E_{thermal}$). So, $E_{total}=ME + E_{thermal}$.

Answer:

D. $E_{total}=ME + E_{thermal}$