What goes up but never comes down?

What does this rebus mean?

O
N
C
E
TIME

What is the longest word in the dictionary?

Two trains start at the same time, one from Bangalore to Mysore and the other from Mysore to Bangalore. if they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

Steffi's daughter Jazelle needs to be picked up from school every day.
Steffi asks one of her colleagues to pick up Jazelle from the school. Steffi devised a password system to confirm that Jazelle goes with the correct colleague only.

The password on Monday was SJM16.
The password on Wednesday was TAW39.

What will the password be for Friday?

10+10 and 11+11 can give you the same answer.

Explain how?

What is wrong in the below Picture?