How can you make number one disappear by adding something to it?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

What is the word or phrase below?
R | E | A | D

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

The following "Brain Bat" means Slow Down.
S
L
O
W

Using the same logic, can you tell us what does the following Brain Bat means ?
E
V
I
G

Which country gets ill every time?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

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

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?