What does this Rebus Picture means ?

What is the centre of gravity?

You see me once in June, twice in November, and not at all in May. What am I?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

Can you find out the remainder when 3^300 is divided by 5?

What have one eye but still cannot see?

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?

A game is being played where eight players can last for thirty-five minutes. Six substitutes alternate with each player in this game. Thus, all players are on the pitch for the same amount of time including the substitutes.

For how long is each player on the pitch?