You have informed your users that you need to bring the machine down at the end of the day to perform routine maintenance. however, prior to shutting the system down, you want to give users fifteen minutes to save data and exit the system. in this lab, your task is to shut the machine down and warn your users as follows:
a. use a 15-minute delay before shutting down.
b. use it is time for a shutdown! as a message to all logged-in users.

shutdown -h +15 It is time for a shutdown!

Explanation:

In a work environment where there is an admin and users connected to the server when the admin wants to Give a 15-minute delay to allow users enough time to save their work data and logout from the system. the command above shuts down after 15 minutes delay and notifies the user with "It is time to shut down!".

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.