What are the permissions of this file? (See “File Permissions and Access Control” in Lab 0.)
Note: The expected answer should look like: -rwxrwxrwx, where the absent permissions are replaced with “-”.
Without the specific file mentioned, it is not possible to determine the permissions of the file or provide a complete answer. The expected answer should include 10 characters representing the file permissions in the form "-rwxrwxrwx", with the first character representing the file type and the remaining nine characters representing the user, group, and others' permissions.
A man is walking away from a lamppost with a light source h = 8 m above the ground. The man is m = 2 m tall. How long is the man's shadow when he is d = 15 m from the lamppost? [Hint: Use similar triangles.]
m
To solve this problem, we can use similar triangles.
Let's say the length of the man's shadow is x.
We have two similar triangles: one formed by the man, his shadow, and the ground, and the other formed by the lamppost, the man's shadow, and the ground.
In the first triangle, the height of the man is the vertical side, and the length of his shadow is the horizontal side.
In the second triangle, the height of the lamppost is the vertical side, and the length of the man's shadow is the horizontal side.
Since the two triangles are similar, we can set up the following proportion:
(man's height) / (man's shadow length) = (lamppost height) / (man's shadow length + shadow length)
Plugging in the given values:
2 / x = 8 / (x + 15)
Now, we can solve for x by cross-multiplying:
2(x + 15) = 8x
2x + 30 = 8x
30 = 6x
x = 30 / 6
x = 5
Therefore, the length of the man's shadow is 5 meters when he is 15 meters away from the lamppost.
To determine the permissions of a file, you can use the `ls -l` command on Linux or macOS, or the `dir` command on Windows. The output will display a sequence of characters indicating the permissions for the file.
For example, if the file permissions are `-rw-r--r--`, it means:
- The first character (`-`) represents the file type. In this case, it is a regular file.
- The next three characters (`rw-`) indicate the permissions for the owner of the file. In this case, the owner has read and write permissions but no execute permission.
- The next three characters (`r--`) indicate the permissions for the group. In this case, the group has only read permission.
- The final three characters (`r--`) indicate the permissions for others or everyone else. In this case, others also have only read permission.
Therefore, the expected answer will vary depending on the actual file permissions.