A block is projected up a frictionless inclined plane with initial speed v0 = 3.53 m/s. The angle of incline is = 32.0°. I need to find (a) How far up the plane does it go? (b) How long does it take to get there? and (c) What is its speed when it gets back to the bottom? I've used F=ma and plugged it into Vf= Vi-at if I rearrange and plug in stuff with F=ma I mgsin(x)=ma the m's cancel out and I'm left with a=mgsin(x) Plugging that into Vf=Vi-at I get Vf=Vi-gsin(x)t If I use that to get b I can say that Vf=0 so 0=3.53sin(32)+9.8sin(32)t The sin(32)'s cancel out and I get -3.53/9.8=t how is t negative?