# Tutor profile: Saber N.

## Questions

### Subject: Basic Math

What is the relationship between $$e^x$$, $$ln(x)$$, and $$log(x)$$?

$$ln(x)$$ is the inverse function of $$e^x$$. The only difference between $$log(x)$$ and $$ln(x)$$ is their base. It is assumed that: $$log(x)$$ = $$log_10(x)$$ $$ln(x)$$ = $$log_e(x)$$ It can be concluded that the $$10^x$$ is the inverse function of $$log(x)$$.

### Subject: Mechanical Engineering

What is the fundamental difference between a compressor and a pump?

Both devices increase the pressure of the working fluid. The conceptual difference between them is that compressors work with gases and pumps work with liquids. Although it seems a small difference, these two devices are very different in their design.

### Subject: Physics

Apply the first law of thermodynamic in your body as a control volume.

Assuming the body is our control volume, the energy-in is the food that we eat. This energy takes two forms: 1- It can be stored in our body, 2- it can be used for regular body functions and doing workouts. The first law (energy equation) states that the energy-in and energy-out are always balanced. That means if I eat too much food without having enough activity, the energy will be stored in my body as fat.

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