Additional Energy problems 3 PDF

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Additional Energy problems 3...

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Energy A 75.0 kg skier rides a 2830 m long lift to the top of a mountain. The lift makes an angle of 14.60 with the horizontal. What is the change in the skier’s gravitational potential energy? (5.24 x 105 J)

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Work A fisherman reels in 12.0 m of line while landing a fish, using a constant forward pull of 25.0 N. How much work does the tension on the line do on the fish? Ans: 300 J

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Work During a tug of war, Team A pulls on team B. Team A consisting of Mohawk’s Physics Professors pull with a force of 3700 N (using specially devised hidden pulleys). Team B consisting of Mohawk’s unsuspecting physics students pull with a force of 2600 N. How much work does team A do if they pull team B toward them a distance of 2.0 m. Ans: 2.2 x 103 J

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Work A student at Mohawk College lifts a backpack filled with physics books, a laptop and other stuff from the floor to a table top. The table top is 29 inches from the floor and the backpack weighs 3.2 kg. How much work is done to lift the backpack? (1in = 2.54cm) (1m = 100cm) Ans: 23 J

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Energy Conservation You throw a 150 g baseball straight up in the air, giving it an initial upward velocity with magnitude 20.0 m/s. Use conservation of energy to find how high it goes, ignoring air resistance. Ans: 20.4 m

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Work A pile driver, a steel hammerhead with a mass 200 kg is lifted 3.00 m above the top of a vertical I-beam being driven into the ground. The hammer is then dropped, driving the Ibeam 40.0 cm into the ground. The vertical rails that guide the hammerhead exert a constant 60.0 N friction force on it. What is the work done by the hammerhead at the point of contact with the I-beam? Ans: 5700 J

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Work The brakes of a truck cause it to slow down by applying a retarding force of 3.0 x 103 N on the truck over a distance of 850 m. What is the work done by this force on the truck? Is the work positive or negative? Why? Ans: -2.6 x 106 J

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Conservation of energy A 12g plastic ball is dropped from a height of 2.5 m. What is its velocity just before striking the ground? Use conservation of energy equation. Ans: 7.0 m/s

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If bananas are on sale for $0.59 / lb, how much does 3 lbs of bananas cost? (1lbm = 0.4356 kg) (1 kg = 2.205 lbm)

Tomatoes are on sale for $2.49 / lb, what is the cost per kilogram? (1kg = 2.205 lbm) ans: $5.49 /kg

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