2) (10p) During a roller derby Annette is approaching Becky from behind with a speed of 3.3 m/s. Right before they collide Becky has a speed of 2.0 m/s. After the collision Anette is bouncing backward with 1.2 m/s. What is Becky's velocity after the collision? Assume that Anette has a mass of 56 kg and Becky has a mass of 70 kg. 6) (6p) When a skier passes point A with a speed of 10 m/s (at an elevation h), her total mechanical energy can be visualized with the energy bar diagram shown on the left. Ekin,i Epoti Draw on the right the energy bar graph for the skier when she passes point B with a speed of 5 m/s (at an elevation of H). Assume there is negligible friction between the skies and the snow and the skier just slides without further energy input. (How does the amount of kinetic energy change? Does the total energy change?) Ekin,f Epot of 7) A diving board of length 3.00 m is supported at a point 1.00 m from the left end by a normal force, and there is a downward force from a bolt at the left end of the board. diving board is of uniform cross section and weighs 260 N. Patricia is standing on th edge of the free end of the diving board. a) (5p) Draw an extended free-body diagram for the diving board into the figure at right. b) (10p) Given that the normal force at the support point is 2000 N, what is Patricia's weight? 1.00 m 2.00 m 5) A 60g tennis ball with an initial velocity of 34 m/s to the right hits a wall and rebounds. a) (5p) The force on the ball by the wall is Force (Time) shown in the figure. What is the 1000 magnitude of the impulse that the wall delivers to the tennis ball? 900 800 700 600 8500 400 300 200 100 0 2 6 8 Time (milli-seconds) The direction of this impulse is to the right to the left. b) (6p) What is the speed with which the tennis ball rebounds? c) (4p) What was the average net force on the ball during the on with the wan Wt BR happen If the BR Fas when it s there isn 8) The figure shows a woman in a pose during push-ups. Her center of mass is indicated in the figure as "CM". Assume the axis of rotation is at her toes (marked with "X"). a) (3p) Draw into the figure the length you would use as lever arm when calculating the torque produced by _ the weight of the woman for an axis at her feet. Clearly label this length as r CM FG 0.97 m b) (5p) Assume the mass of the woman is 54 kg. The distance between her feet and her center of mass is 0.97 m. The angle shown in the figure is 0 = 30. Calculate the torque produced by her weight about an axis located at her toes. axi 9) (7p) Crater Lake in Oregon is the deepest lake in the US. At the deepest part, the total depth is 594.4 m. What is the absolute pressure at a point 594.4 m below the surface of the water? 10) A sea otter floats on a lake. a) (4p) Draw a free-body diagram for the otter. The mass of the otter is 25-kg and we estimate that 60% of its body volume is below the water level. b) (5p) What is the buoyant force on the otter? of the of c) (5p) What is the average (mass) density of the otter? Provide your reasoning. 12) (6p) When a blood clot forms within a blood vessel it can obstruct blood flow, a condition called thrombosis. Considering that blood is a viscous fluid, and that the blood clot has effectively reduced the radius of the blood vessel to rclot = 0.65 normal what is the resulting volume flow rate as compared to the volume flow rate of a normal (unobstructed) blood vessel? 65% of the normal blood flow rate 42% of the normal blood flow rate 27% of the normal blood flow rate 18% of the normal blood flow rate. uch 1) (10p) Alyssa tries out the water slide at the city pool (shown in the figure). The starting point is 11.3 m above the ground (which you can assume is the same level as the surface of the water). She pushes off at the top of the slide and starts with an initial speed of 2.0 m/s. If the slide has negligible friction, how fast is Alyssa when she exits at the bottom of the slide? Alyssa has a mass of 45 kg.