WORKSHEETS FÍSICA PARA GRADOS 6 Y 5, Ejercicios de Física

¡Descarga WORKSHEETS FÍSICA PARA GRADOS 6 Y 5 y más Ejercicios en PDF de Física solo en Docsity! ckK-12 CK-12 Physics Concepts - Intermediate Answer Key Chapter 8: Work, Power, and Simple Machines 8.1 Work Practice Questions 1. What definition is given in the video for energy? 2. What is the definition given in the video for work? 3. What unit is used in the video for work? The following website contains practice questions with answers on the topic of work. http:/Avww.sparknotes.com/testprep/books/sat2/physics/chapter7section6.rhtml Answers 1. Energy is the ability to do work. 2. Work is the energy transferred by a force, given by force times distance. 3. The units used in the video for work are Newton-meters or Joules. Review Questions 1. How much work is done by the force of gravity when a 45 N object falls to the ground from a height of 4.6 m? 2. A workman carries some lumber up a staircase. The workman moves 9.6 m vertically and 22 m horizontally. If the lumber weighs 45 N, how much work was done by the workman? 3. A barge is pulled down a canal by a horse walking beside the canal. If the angle of the rope is 60.0”, the force exerted is 400. N, and the barge is pulled 100. m, how much work did the horse do? Horse direction of motion ckK-12 Answers 1. Using w=fd:45 N+*4.6m > Gravity does 207 Nm of work. 2. The only force the workman is working against is the force of gravity, so only the vertical change is relevant. Using w=fd: 9.6m*45 N > The workman did 432 Nm of work. 3. Using w=fd :[(400 N*cos 60 *][100 m| The horse does 20,000 Nm of work. 8.2 Power Practice Questions 1. What is the difference between positive and negative work? 2. What are the standard units for power? 3. What is horsepower? 4. How many grandfather clocks could you power with the same amount of power used by a single light bulb? Answers 1. Positive work is the energy you put into a system, while negative work is the power that comes out. 2. The standard units for power are Watts, defined as Joules/sec (J/s). 3. Horsepower was how James Watt described the power of his machines to other people. 4. You could run almost 300,000 clocks on the same amount of power as a single light bulb. Review Questions 1. If the circumference of an orbit for a toy on a string is 18 m and the centripetal force is 12 N, how much work does the centripetal force do on the toy when it follows its orbit for one cycle? 2. A 50.0 kg woman climbs a flight of stairs 6.00 m high in 15.0 s. How much power does she use? 3. Assuming no friction, what is the minimum work needed to push a 1000. kg car 45.0 mup a 12.5" incline?