AP CollegeBoard Test Booklet Unit 6 HW FRQs block. If there is more than one specific reason a diagram is incorrect, identify each of the reasons. Please respond on separate paper, following directions from your teacher. (c) Briefly explain why slightly increasing the force F exerted by the rope on the block (without changing the angle 0) would cause a decrease in the friction force. Please respond on separate paper, following directions from your teacher. d) The friction force f is f = u(W - F sin 0), where W is the weight of the block and F is the force exerted by the rope. Explain why this equation is consistent with the claim that an increase in F would cause a decrease in the friction force. Please respond on separate paper, following directions from your teacher. Rope ty Block *+X M Floor The rope is now attached to the center of the top of the block, as shown above. The force exerted by the rope is initially zero newtons at time t = 0. The force steadily increases, becomes equal to the block's weight W at time t1, and continues to increase further. Three students sketch the graphs shown below to represent the speed of the block as a function of time t. One of the graphs is consistent with this scenario, while the other graphs are not consistent with this scenario. Page 26 of 31 AP Physics 1AP Collegellard Unit 6 HW FRQs Test Booklet time 25 minutes) This question is a long free-response question. Show your work for each part of the question. (15 points, suggested Rope Block M Floor A block of mass M is pulled by a rope that makes an angle 0 (theta) above the horizontal, as shown above. The coefficient of kinetic friction between the block and floor is / (mu). The block is initially at rest and starts accelerating to the right along the floor. Three students each draw a diagram to indicate all of the forces that are exerted on the block as it moves. In the students' diagrams, which are shown below, the lengths of the arrows indicate the relative magnitudes of the forces. Normal 1_ Normal_ _ _ Normal Rope Rope Rope Friction Friction Friction Weight Weight Weight Student 2's Diagram Student 3's Diagram Student 1's Diagram Only one of the students has drawn a diagram that could correctly represent the forces. The other two students' diagrams are incorrect. (a) Which student has drawn a diagram that could correctly represent the forces exerted on the block? Please respond on separate paper, following directions from your teacher. (b) For the incorrect student diagrams, explain why the diagram could not represent the forces exerted on the AP Physics 1 Page 25 of 31