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Physics 20: SU IVIVER Assignment 10 Unit C Module 2, Lesson 2: Conservation of Mechanical Energy lesson 2 of this assignment is worth 13 marks. The value of each question is noted in the left margin in parentheses. 7. A child rides a toboggan down an icy hill all the way to the bottom. If the hill is frlctlonless and air reslstanoe is negllgi ole, what can he said about the mechanlcal energyr [the sum of the kinetic and potential energies} at any point down the hill? {1) 3_ Use the following information to answer parts a-h. The strings in a compound how behave approximately like a spring. A howstring is pulled back 0.60 In with a maximum force of 267 N (AKA a 60-pound draw weight) to shoot an 18 g arrow. Assume energy is conserved. a} At what speed would the arrow be launched? (Note: W = PM uses the average force while F = 4a uses the instantaneous force.) {3) b] If the arrow were shot straight upward, how far would it rise? (This would be extremely dangerous. do not ever shoot an arrow upward.) {2) 9. Due to conservation of energy, a grandfather clock is able to keep time since the cycle of the pendulum inside remains constant. If the maximum height of a pendulum in a clock is 15.0 cm higher than at the equilibrium position, what is the maximum speed of the pendulum? (2) 10. Some racetracks use "compression barriers" which behave like springs to absorb some of the energy of the impact when a car hits the guardrail. If a 1500 kg racecar hits the guardrail at a speed of 70.0 m/s and the compression barrier has a spring constant of 73.5 kN/m, what length would the barrier have to be to stop the car? (2)Physics 20: SUMMER Assignment 10 11. A rubber-band slingshot behaves approximately like a spring. If an eraser is shot directly upward, explain in point-form how the gravitational potential energy, spring potential energy, and kinetic energy change at the Maximum stretch of the rubber band Moment the eraser passes through the rubber band's equilibrium Maximum height of the eraser's flight (3)