1. The problem statement, all variables and given/known data. Find the force P and theta that will start the block to move. The illustration can be found at the attachments. Given: W= 200 N Radius of the circle 400 mm length of the block 100 mm The unknowns are the P and theta. 2. Relevant equations. Summation of Fx=0 Summation of Fy=0 Those are the equations that I see that can be used. 3. The attempt at a solution. Note that there is no normal force between the cylinder and the surface since the system will start to move. There are three forces acting on the system: the weight (W), force P, and normal force between the block and the cylinder (Nb). The horizontal angle of the Nb can be acquired by using right triangle where hypotenuse equals the radius and and one leg equals radius minus length of the block. By using sine function, the angle can be acquired. There are three unknowns left: P, theta, and Nb. There are only 2 equations that I can see: the summation of horizontal component and the summation of vertical component. What should I do? Thank you.