Einstein

Even if you haven’t studied physics (recently or ever!), you might have heard that $E = mc^2$, wherein $E$ represents energy (measured in Joules), $m$ represents mass (measured in kilograms), and $c$ represents the speed of light (measured approximately as 300000000 meters per second), per Albert Einstein et al. Essentially, the formula means that mass and energy are equivalent.

In a file called einstein.py, implement a program in Python that prompts the user for mass as an integer (in kilograms) and then outputs the equivalent number of Joules as an integer. Assume that the user will input an integer.

Hints

Recall that input returns a str, per docs.python.org/3/library/functions.html#input.
Recall that int can convert a str to an int, per docs.python.org/3/library/functions.html#int.
Recall that Python comes with several built-in functions, per docs.python.org/3/library/functions.html.

Demo

Before You Begin

Log into cs50.dev, click on your terminal window, and execute cd by itself. You should find that your terminal window’s prompt resembles the below:

Next execute

mkdir einstein

to make a folder called einstein in your codespace.

Then execute

cd einstein

to change directories into that folder. You should now see your terminal prompt as einstein/ $. You can now execute

code einstein.py

to make a file called einstein.py where you’ll write your program.

How to Test

Here’s how to test your code manually:

Run your program with python einstein.py. Type 1 and press Enter. Your program should output:
```
90000000000000000
```
Run your program with python einstein.py. Type 14 and press Enter. Your program should output:
```
1260000000000000000
```
Run your program with python einstein.py. Type 50 and press Enter. Your program should output
```
4500000000000000000
```

You can execute the below to check your code using check50, a program that CS50 will use to test your code when you submit. But be sure to test it yourself as well!

check50 cs50/problems/2022/python/einstein

Green smilies mean your program has passed a test! Red frownies will indicate your program output something unexpected. Visit the URL that check50 outputs to see the input check50 handed to your program, what output it expected, and what output your program actually gave.

How to Submit

In your terminal, execute the below to submit your work.

submit50 cs50/problems/2022/python/einstein