I have three Physics questions that I need help with:

1) A tire makes 65 revolutions while slowing from 100km/h to 80km/h, the tire's radius is 40 cm, how much time will it take to stop if it keeps slowing at a constant rate?

2) There is a 70kg man standing on a beam that is 100kg. There is a fulcrum 1 m to the right from the left end and another fulcrum 4 m to the right from the left end. The man is standing to the right of the right-most fulcrum. How far can he go to the right before the beam tips. Here's a rough diagram: ______________I___
1m/\ 3m /\ 2m I=man

3) There is a 75kg person sitting on the edge of a T shaped counter that is 125cm wide and 85 cm tall. The bottom is 50 cm wide. What is the torque that is exerted on the bottom of the counter? Here is another rough diagram: _________________I
|____-125cm- _____| |
| | 85 cm
| -50 cm-| |
|_______|

Sorry, my diagrams didn't turn out like they did in the typing box. The bottom one is a T shape.

My current equivalent grade, I believe is grade 11, but I'll try to do the first one, I've not got much time...

1) Ok, 65 revolutions... Radius 40 cm, so circulference, .
Hence, distance covered from 100km/h to 80 km/h = .

What I now need is an equation regrouping distance, final and initial speed (perhaps s = ut + (1/2)at^2? I'm not so good at those formulae) Anyway, I hope someone will continue from here, or yourself, jaja, perhaps can take it from here? You will have the time taken from 100km/h to 80km/h, then multiply that time by 5 [got by 100/(100-80)]for the speed to come to zero.