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

On the dull night when the blonde was dozing, she heard an odd clamour and she saw that there was a bizarre man with a gun simply outside her home. So she raced to the telephone to call the police, however, she can't dial 911. Why?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?

What has hands, but can’t clap?

When does a USA Potato change its nationality?

Look at me. I can bring a smile to your face, A tear to your eye, Or even a thought to your mind. But, I can't be seen. What am I?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

A woman shoots her husband.

Then she holds him under water for over 5 minutes.

Finally, she hangs him.

But 5 minutes later they both go out together and enjoy a wonderful dinner together.

How can this be?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?