F 4. Consider a round cell of radius r, sliding freely along a surface, until it binds by a single flexible tether of length d. It rotates and then stops. The tether must point in the direction of the cell midpoint when the cell stops moving, as shown in the figure to the right. The fluid exerts a drag force F on the cell through the cell mid-point, parallel to the surface. What are all support reactions, in terms of F, r, and d? (Hints: 1) The tether is not the only support reaction. 2) You need to know the sin and cos of an unknown angle to solve your equilibrium equations. Use geometry to find these values. Draw a right triangle that includes the unknown angle, and at least two legs with a known length (e.g. "r" or "d" or "r+d"). Then use stuff you learned long agao about triangles to find sin or cos of the angle from the known distances, r and d.)

F 4. Consider a round cell of radius r, sliding freely along a surface, until it binds by a single flexible tether of length d. It rotates and then stops. The tether must point in the direction of the cell midpoint when the cell stops moving, as shown in the figure to the right. The fluid exerts a drag force F on the cell through the cell mid-point, parallel to the surface. What are all support reactions, in terms of F, r, and d? (Hints: 1) The tether is not the only support reaction. 2) You need to know the sin and cos of an unknown angle to solve your equilibrium equations. Use geometry to find these values. Draw a right triangle that includes the unknown angle, and at least two legs with a known length (e.g. "r" or "d" or "r+d"). Then use stuff you learned long agao about triangles to find sin or cos of the angle from the known distances, r and d.)