<< Thread moved to the HH forums from the technical physics forums, so no HH Templatge is shown >> So I have this question that says, "Someone at a third floor window (12 m above ground) hurls a ball downward at 45 degrees at a speed of 25.0 m/s. How fast will it be traveling when it strikes the sidewalk?" I broke it up into horizontal and vertical components, but I don't know where to use them in solving for it. I tried to use the equation Yf=Yi+Vi(t)+(1/2)(a)(t)^2 but then I got confused. I feel like the question is asking me for an acceleration but I thought the acceleration in all projectile motion questions was -9.8 (gravity). So if I use the equation I was wanting to I would have put: Yf=0, Yi= 12, Vi=-25.0, and a=-9.8. However, that would have given me time which I don't think is what I'm being asked to find.