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

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

In a town, there are four houses located at different distances from each other. Following are the distances:

The third house is 60 meters apart from the first house.
The fourth house is 40 meters apart from the second house.
The third house is 10 meters nearer to the fourth house than it is to the second house.

Can you find out the distance between the fourth and the first house?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

Can you name some countries which do not have the alphabet 'A' in them?

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

John was piloting a plane behind a car but was never able to overtake it. Why?

Can you find a rabbit in the given picture?

What goes up but never comes down?