The problem statement, all variables and given/known data Ok, I have a couple problems that I'm having trouble with. Bear with me, my physics teacher can be a little creative...lol. 1. I am an expert swan diver. If I am jumping off a 3m diving board, what is the velocity with which I strike the water? If the water brings me to rest in 0.3 seconds, what is the force the water applies to me? 2. Driving along in your 850 N Mini Cooper you pass by a hemp clothing yard sale and slam on your brakes. If you were traveling 20 m/s and your brakes apply a force of 8000 N in the opposite direction, how long does it take you to stop? How far do you skid? 3. Super Mario, who weighs 5 kg, is standing on a platform, which weighs 25 kg. Seeing Bowser in the distance he jumps off the platform with a speed of 3 m/s to the right. What is the final velocity of the platform? Relevant equations Vi = √2ghi F∆t = -mVi/∆t F∆t = mVf - mVi m1V1,i + m2V2,i = m1V1,f + m2V2,f I'm not sure if there are any others that I need, but I have a feeling that I'm missing something. The attempt at a solution For the first problem, I used Vi = √2ghi and found the man to be going 7.7 m/s. Then I tried to use the equation F∆t = -mVi/∆t, but I don't have the mass. Is there another equation to use or did my teacher just forget to include mass? (he does that a lot) For the second one I think it has something to do with the impulse momentum theorem, but how would I find the skid distance with that? For the third one, I'm pretty sure I need to use m1V1,i + m2V2,i = m1V1,f + m2V2,f. But I don't really know where to start. EDIT: I just tried to solve number 3 and I got -0.6 m/s. Is this correct? I'm still not too sure about the other problems though.