I don't want to do your homework for you, but here are some equations from high school physics:

Question 1:

v² = u² + 2as

where v = final velocity, u = initial velocity, s = distance.

Question 2:

Very easy if you think about it. Every second, the P-wave travels (7.0 - 3.6) = 3.4km more. So, in 19 seconds...

Is this a joke post?