Ask and answer questions here. You learn both ways.

DISCUSSION and HINTS

Recall the following four-step plan outline in the lecture book and discussed in lecture:

Step 1: FBDs
Draw a free body diagram for the block.

Step 2: Kinetics (Newton’s 2nd Law)
Since the position of the block is given in terms of a radial distance r and a rotation variable θ, a polar description is recommended for resolving the forces acting on the block.

Step 3: Kinematics
Since you have used a polar description for resolving forces, you should also use a polar description for acceleration; that is, a_P = (r_ddot – r*θ_dot²)e_r +(r*θ_ddot + 2r_dot*θ_dot) e_θ. What is true about r_dot and r_ddot when the cable remains taut?

Step 4: Solve
At this point you will have two equations in terms of two unknowns: the normal contact force and the tension force. Does your answer for the normal force on the block make sense?