SPH 3UI Name:__________________________ Unit Test #3: Energy, Work, Power ( /47) There are three parts to this test. Please complete all three. Part 1: Multiple Choice (10 marks; 1 mark each) Please place all “part one” answers in the grid below. All questions worth one mark. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 1. Sue Case uses a force of 45.0 N to pull her luggage a distance of 1.50 m across a driveway. Calculate the amount of work that she does on the luggage. A) 30.0 J B) 67.5 J C) 0.033 J D) 90.0 J 2. A 2.2 kg pot of water is sitting on the top of a stove. If water has a specific heat capacity of 4.18x103 J/(kg∙C) and 7.40 x105 J of energy is added to the water by the oven, what will be the change in the water’s temperature? A) 19.5 C B) 80.0 C D) 638 J C) 6.19 x 108 C 3. The amount of energy that must be added to a substance to raise 1.00 kg of the substance by 1oC is the substance's: a) temperature b) latent heat c) thermal energy d) specific heat capacity 4. A gardener pushes a lawnmower by exerting a constant force of magnitude 9.3 N. If this force does 87 J of work on the lawnmower while pushing it 11 m across level ground, what is the angle between the applied force and the horizontal? B) 42 A) 1.0 C) 32 D) 89 5. Shel Vigo is diving from a tower 10.0 m above the water. When she is 5.0 m above the surface of the water, her: A) B) C) D) velocity is half of the velocity that she will have when she reaches the water. potential energy, with respect to the water, and her kinetic energy are about equal. total mechanical energy is about half of her initial energy. her kinetic energy is about zero. 6. Which of the following is not a valid unit for joules? A) kg m2 / s2 B) N m C) kg m / s D) J 7. A vampire is standing close to a human. If the vampire breathes on the human (making her feel warmer), he has transferred thermal energy through: A) Conduction B) Convection C) Radiation D) Onions 8. A toy cart moves with a kinetic energy of 10. J. If its speed is doubled, what will its new kinetic energy be? A) 10. J B) 20. J C) 40. J D) 120 J 9. A 72 kg skier arrives at the top of the ski hill and has 9.2 x 105 J of gravitational potential energy. How high is the ski hill relative to sea level? A) 1. 3 x 103 m B) 1. 5 x 103 m 3 C) 1. 7 x 10 m D) 6.4 x 103 m 10. At a county fair, a dirt bike is doing tricks off a ramp. When the driver approaches a ramp at a speed of v, he achieves a height of h. If he later approaches the ramp with an increased speed of 3v, how high will he go in terms of h? A) h B) 3h C) 6h D) 9h SPH 3UI Name:__________________________ Part 2: Short Answer (12 marks) Write each answer in the corresponding box. Your rough work will not be graded. 11. A 500. g rock is thrown straight down from a bridge to the water 5.20 m below. If the rock strikes the water at a speed of 12.5 m/s, the initial speed of the rock was _____________ m/s. (Record your answer to three digits.) 11. _________________________ m/s 12. A 5.00 kg sack of potatoes is raised to a height of 2.00 m and then thrown at a constant velocity of 2.00 m/s onto a truck. What is the kinetic energy of the potatoes? 12. __________________________ J Use the following information to answer the next question. 13. When placed in order from the greatest amount of kinetic energy to the least, the order of the four different positions of the roller coaster car labeled on the diagram is: 14. A 10.0 kg box of cucumbers is pushed at a constant speed along a frictionless incline as shown in the diagram. The change in energy in moving the box from the bottom to the top of the incline is: _____________ J . (Record your answer to three digits.) 14. a) height of ramp: ________ m (helpful info!) b) E: ________________ J h 30 15. A 2.0 kg ball moving at 2.0 m/s is rolling toward an inclined plane, as shown below. It eventually rolls up the hill to a position near the top where it momentarily stops prior to rolling back the incline. Assume no friction and no air resistance. Darken the bars of the energy bar chart in order to demonstrate the amount of kinetic energy (KE), potential energy (PE) and total mechanical energy at the position A and position B (2 marks). SPH 3UI 16. Given one example of: Type of Heat Transfer Convection Name:__________________________ Example Conduction Radiation 17. State two specific conditions when no work is done. Give an example of each. 3: Full Soluitons (25 marks) Please provide NEAT and ORGANIZED full solutions. Draw diagrams and list your given and required information. Given (diagram may be helpful) Assumptions if necessary Equation(s) Rearrange / Substitute with units / Solve as you wish Statement (take note of sig fig!) 18. A basketball player makes a free throw shot at the basket. The basketball leaves the player’s hand at a speed of 7.2 m/s from a height of 2.21 m above the floor. Determine the speed of the basketball as it goes through the hoop, located 3.05 m above the floor. Figure 1 shows the situation. (Nelson: p196) ___ 5 Figure 1: Free Throw Shot 19. A catcher stops a 40.2 m/s pitch in his glove, bringing it to rest in 0.179 m. If the force exerted by the catcher is 785 N, what is the mass of the ball? ___ 5 SPH 3UI Name:__________________________ 20. A 1000. kg wooden roller coaster, with its passengers, starts from rest at point A. If the final speed of the roller coaster at point E is7.0 m/s: a) What is the increase in thermal energy due to the friction of the track? b) What is the efficiency of the roller coaster? (ie: how well does the roller coaster transfer the mechanical energy to its final mechanical energy?) Wooden Roller Coaster: Consider Friction 7 21. A snowboarder starts from rest at the top of a frictionless hill of height 25.0 m. When the snowboarder reaches the bottom, he goes across a flat section with a coefficient of friction of 0.250. How far will the snowboarder travel before coming to a stop? ___ 5 22. Washing the dishes requires 55.5 kg of water. Tap water is at a temperature of 10.0C and the diswasher's preferred water temperature is 45.0C. Find the amount of energy 3 required to heat the water. cwater = 4.18 x 10 J ___ 3

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