Here is the problem: The velocity of a 2.3 kg block sliding down a frictionless inclined plane is found to be 1.12 m/s. 1.20 sec. later it has a velocity of 5.08 m/s. What is the angle of the plane with respect to the horizontal? There is quite a bit of information here. I have gathered some of the vital details and will demonstrate what I have thus far, which may be correct or incorrect. This is a Newton's Second Law Problem (I believe). F=m*a accel=v2-v1/t2-t1 = (5.08 - 1.12)/(1.2-0)= 3.3m/s^2 So, at this point I have mass and acceleration to work with. I know that there are three forces acting on the block, so I have constructed a free body diagram. Also, solving for Fgrav would require w=m*g. w=(2.3)*(3.3) therefore w=22.545 [N]. Most problems involving an inclined plane have theta given. However, I have not been able to find any problems similar to this one with theta unknown. Any help or website resources would be greatly appreciated.