Set 4- Work and Energy

Set 4- Work and Energy - Sonia Rahangdale - PHY 231 Fall...

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Unformatted text preview: Sonia Rahangdale - PHY 231 Fall 2006 Set 04 (10/03) 1 Due date: Tue Oct 3 23:59:00 2006 Calculate the change in potential energy of a 78.0 kg man when he takes an elevator from the first floor to 45th floor, if the distance between floors is 4.35 m. You are correct. Your receipt is 155-1469 A 66.0 kg diver is 1.70 m above the water, falling at speed of 9.10 m/s. Calculate her kinetic energy as she hits the water. (Neglect air friction) You are correct. Your receipt is 155-1473 Select which of the following statements are True or False. Assume Newtonian Mechanics. A. B. C. D. E. F. Choices: True, False. A simple machine may reduce the force required to do a task. The work required to lift a mass one meter depends on the speed at which it is raised.. Less power is required while slowly lifting a box than while lifting it up quickly. The acceleration of an object is same in all inertial reference frames. A particle's kinetic energy can change without having any net work done it. The work done by a constant force acting on an object is equal to the magnitude of the force times the distance the object moves. If the wire is frictionless, find the speed of the bead at C. You are correct. Your receipt is 155-3111 h1 h2 A 31.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 22.00 m. When she is partway down the slide, at a height h2 of 9.00 m, she is moving at a speed of 8.40 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.). You are correct. Your receipt is 155-1753 H h You are correct. Your receipt is 155-1487 A skier (m=63.0 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally. If h = 5.90 m and D = 13.5 m, find H. D A 0.438 kg bead can slide on a curved wire as seen in the figure. You are correct. Your receipt is 155-2275 Find her total kinetic energy as she reaches the ground. You are correct. Your receipt is 155-2617 Assume h1 = 4.75 m and h2 = 2.28 m. If the wire is frictionless and the bead is released with an initial speed of 1.12 m/s in the forward direction then find the speed of the bead at B. You are correct. Your receipt is 155-2599 Sonia Rahangdale - PHY 231 Fall 2006 Set 04 (10/03) 3 A mass M=0.690 kg is initially at rest on a horizontal surface. A force, given by F = Fx i, acts on M. The horizontal component Fx is shown by the histogram below as function of position along the x-axis. There is also a kinetic frictional force of 0.50 N between the mass and the surface. F M 1234567890123 1234567890123 1234567890123 1234567890123 1234567890123 1234567890123 1234567890123 1234567890123 5 4 3 2 1 0 -1 -2 -3 -4 -5 0 1 2 3 4 5 6 7 x-coordinate, (m) 8 9 10 x-component of F, (N) A man pulls a crate of mass 69.0 kg across a level floor. He pulls with a force of 176.0 N at an angle of 22.0 above the horizontal. When the crate is moving, the frictional force between the floor and the crate has a magnitude of 118.0 N. If the crate starts from rest, how fast will it be moving after the man has pulled it a distance of 2.50 m? You are correct. Your receipt is 155-1479 Calculate the kinetic energy of M as it reaches 9 m. You are correct. Your receipt is 155-1916 In the Biomedical and Physical Sciences building at MSU there are 128 steps from the ground floor to the sixth floor. Each step is 17.1 cm tall. It takes 2 minutes and 33 seconds for a person with a mass of 64.3 kg to walk all the way up. How much work did the person do? M h A 1.80 kg box slides down a rough incline plane from a height h of 1.39 m. The box had a speed of 2.11 m/s at the top and a speed of 1.68 m/s at the bottom. Calculate the mechanical energy lost due to friction (as heat, etc.). You are correct. Your receipt is 155-2601 What was the average power performed by the person during the walk? You are correct. Your receipt is 155-2169 How many food Calories did the person burn during the walk? (Do not enter unit for this part.) You are correct. Your receipt is 155-2852 You are correct. Your receipt is 155-1755 A crane at a construction site lifts a concrete block with a mass of 426 kg from the ground to the top of a building with a height of 19.5 m. How much work did the motor of the crane do? (Assume zero energy loss in the lifting mechanism due to friction.) You are correct. Your receipt is 155-2611 If the duration of the lift was 2.55 minutes, then what was the average power performed by the crane? You are correct. Your receipt is 155-2179 Sonia Rahangdale - PHY 231 Fall 2006 Set 04 (10/03) 5 A car of mass 820.0 kg accelerates away from an intersection on a horizontal road. When the car speed is 40.3 km/hr (11.2 m/s), the net power which the engine supplies is 4300.0 W (in addition to the extra power required to make up for air resistance and friction). Calculate the acceleration of the car at that time. You are correct. Your receipt is 155-1475 A car (m = 650.0 kg) accelerates uniformly from rest up an inclined road which rises uniformly, to a height, h = 32.0 m. Find the average power the engine must deliver to reach a speed of 25.9 m/s at the top of the hill in 20.5 s(NEGLECT frictional losses: air and rolling, ...) 1 67890 1 1 12345 67890 1 67890 1 67890 12345 67890 1 12345 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 1 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 12345 67890 12345 67890 12345 67890 1 12345 67890 12345 67890 12345 67890 12345 67890 12345 67890 12345 67890 12345 12345 67890 12345 12345 67890 12345 67890 12345 A 0.190 kg dart is fired straight up. Find the vertical distance the dart travels from its position when the spring is compressed to its highest position. You are correct. Your receipt is 155-2635 The same dart is now fired horizontally from a height of 4.90 m. The dart remains in contact until the spring reaches its equilibrium position. Find the horizontal velocity of the dart at that time. h 1 67890 1 1 12345 67890 1 67890 1 67890 12345 67890 1 1234 12345 12345 67890 12345 67890 1 1234 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 1234 12345 67890 12345 67890 12345 67890 1 12345 67890 12345 67890 12345 67890 12345 67890 12345 67890 12345 67890 12345 12345 67890 12345 12345 67890 12345 67890 12345 You are correct. Your receipt is 155-2544 Find the horizontal distance from the equilibrium position at which the dart hits the ground. You are correct. Your receipt is 155-2112 You are correct. Your receipt is 155-1485 It takes a minimum distance of 41.14 m to stop a car moving at 11.0 m/s by applying the brakes (without locking the wheels). Assume that the same frictional forces apply and find the minimum stopping distance when the car is moving at 26.0 m/s. You are correct. Your receipt is 155-1759 A small mass m slides with negligible friction down an incline at an angle of 25.76 with respect to the horizontal. It then drops down to a horizontal surface and bounces elastically back up as shown. T V X Q U S The picture is to scale. It shows the position of the mass at equal time intervals starting from rest at V. The height of the mass at R is the same as at U. Click here to view the motion of the mass m. A. B. C. D. E. F. Choices: greater than, less than, equal to. that at U. The mechanical energy of m at P is The speed change between V and T is between T and Q. that at R. The velocity of m at U is The speed of m at X is that at P. at S. The size of the total force on m at P is The size of the total force on m at T is at U. P R A car (m = 730.0 kg) travelling on a level road at 27.0 m/s (60.48 mph) can stop, locking its wheels, in a distance of 58.0 m (190.29 ft). Find the size of the horizontal force which the car applies on the road while stopping on the road. You are correct. Your receipt is 155-2703 Find the stopping distance of that same car when it is traveling up a 19.5 slope, and it locks its wheels while traveling at 27.0 m/s (60.48 mph). Assume that k does not depend on the speed. You are correct. Your receipt is 155-2100 You are correct. Your receipt is 155-2204 The potential energy stored in the compressed spring of a dart gun, with a spring constant of 62.50 N/m, is 0.900 J. Find by how much is the spring is compressed. You are correct. Your receipt is 155-2293 Sonia Rahangdale - PHY 231 Fall 2006 Set 04 (10/03) 7 The labeled graphs below represent the upward trajectories of 4 bodies, two sliding upwards on frictionless inclines and two in free flight. Note that all 4 bodies reach the same maximum height (9 meters) after traveling from the same initial elevation (0 m). 10 9 Vertical position, y, (m) 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Relative horizontal position, x, (m) N Q P R A. B. C. D. E. F. Choices: greater than, less The initial speed of P is The initial speed of Q is The initial speed of Q is The time of travel of R is The time of travel of Q is The time of travel of P is than, equal to. that of R. that of N. that of P. that of P that of N that of N. You are correct. Your receipt is 155-1877 Printed from LON-CAPA MSU Licensed under GNU General Public License ...
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This homework help was uploaded on 04/10/2008 for the course PHY 231 taught by Professor Smith during the Spring '08 term at Michigan State University.

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