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Work and Energy

x. Work and Energy. Work and Energy 06. Ref: Sec. 6.1. 01. Work. Work and Energy 06. A 500-kg elevator is pulled upward with a constant force of 5500 N for a distance of 50.0 m . What is the net work done on the elevator?. (A) 2.75 × 10 5 J (B) -2.45 × 10 5 J

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Work and Energy

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  1. x Work and Energy Work and Energy 06

  2. Ref: Sec. 6.1 01 Work Work and Energy 06 A 500-kg elevator is pulled upward with a constant force of 5500 N for a distance of 50.0 m. What is the net work done on the elevator? (A) 2.75 × 105 J (B) -2.45 × 105 J (C) 3.00 × 104 J (D) -5.20 × 105 J Work and Energy 06

  3. Ref: Sec. 6.1 02 Work Work and Energy 06 Matthew pulls his little sister Sarah in a sled on an icy surface (assume no friction), with a force of 60.0 N at an angle of 37.0° upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew? (A) 185 J (B) 433 J (C) 575 J (D) 720 J Work and Energy 06

  4. Ref: Sec. 6.2 03 Work Work is the product of force times distance Work and Energy 06 A force moves an object in the direction of the force. The graph shows the force versus the object's position. Find the work done when the object moves from 0 to 6.0 m. (A) 20 J (B) 40 J (C) 60 J (D) 80 J Work and Energy 06

  5. Ref: Sec. 6.3 04 Work/Energy Theorem Work Work and Energy 06 A horizontal force of 200 N is applied to move a 55-kg cart (initially at rest) across a 10 m level surface. What is the final kinetic energy of the cart? (A) 1.0 × 103 J (B) 2.0 × 103 J (C) 2.7 × 103 J (D) 4.0 × 103 J Work and Energy 06

  6. Ref: Sec. 6.3 05 Work Work/Energy Theorem Kinetic Energy Work and Energy 06 If it takes 50 m to stop a car initially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s under the same condition? (A) 50 m (B) 100 m (C) 200 m (D) 400 m Work and Energy 06

  7. Ref: Sec. 6.3 06 Work Work/Energy Theorem Kinetic Energy Work and Energy 06 A spring-driven dart gun propels a 10-g dart. It is cocked by exerting a constant force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has negligible mass? (A) 10 m/s (B) 14 m/s (C) 17 m/s (D) 20 m/s Work and Energy 06

  8. Ref: Sec. 6.3 07 Work Work and Energy 06 A 100-N force has a horizontal component of 80 N and a vertical component of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizontally along the floor. What is the cart's final kinetic energy? (A) 200 J (B) 160 J (C) 120 J (D) zero Work and Energy 06

  9. Ref: Sec. 6.4-6.5 08 Gravitational Potential Energy Work and Energy 06 A 15.0-kg object is moved from a height of 7.00 m above a floor to a height of 15.0 m above the floor. What is the change in gravitational potential energy? (A) 1030 J (B) 1176 J (C) 1910 J (D) 2205 Work and Energy 06

  10. Ref: Sec. 6.4-6.5 09 Gravitational Potential Energy Work and Energy 06 A 400-N box is pushed up an inclined plane. The plane is 4.0 m long and rises 2.0 m. If the plane is frictionless, how much work was done by the push? (A) 1600 J (B) 800 J (C) 400 J (D) 100 J Work and Energy 06

  11. Ref: Sec. 6.4-6.5 10 Spring Potential Energy Work and Energy 06 A spring is characterized by a spring constant of 60 N/m. How much potential energy does it store, when stretched by 1.0 cm? (A) 3.0 × 10-3 J (B) 0.30 J (C) 60 J (D) 600 J Work and Energy 06

  12. Ref: Sec. 6.4-6.5 11 Spring Potential Energy Work and Energy 06 A spring with a spring constant of 15 N/m is initially compressed by 3.0 cm. How much work is required to compress the spring an additional 4.0 cm? (A) 0.0068 J (B) 0.012 J (C) 0.024 J (D) 0.030 J Work and Energy 06

  13. Ref: Sec. 6.6-6.7 12 Conservation of Energy Work and Energy 06 A skier, of mass 40 kg, pushes off the top of a hill with an initial speed of 4.0 m/s. Neglecting friction, how fast will she be moving after dropping 10 m in elevation? (A) 7.3 m/s (B) 15 m/s (C) 49 m/s (D) 196 m/s Work and Energy 06

  14. Ref: Sec. 6.6-6.7 13 Kinetic Energy Energy Potential Energy Work and Energy 06 A 1.0-kg ball falls to the floor. When it is 0.70 m above the floor, its potential energy exactly equals its kinetic energy. How fast is it moving? (A) 3.7 m/s (B) 6.9 m/s (C) 14 m/s (D) 45 m/s Work and Energy 06

  15. Ref: Sec. 6.6-6.7 14 Cons. of Energy Kinetic Energy Potential Energy Work and Energy 06 A roller coaster starts with a speed of 5.0 m/s at a point 45 m above the bottom of a dip as shown in the diagram. Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip? (A) 12 m/s (B) 14 m/s (C) 16 m/s (D) 18 m/s Work and Energy 06

  16. Ref: Sec. 6.6-6.7 15 Cons. of Energy Kinetic Energy Potential Energy Work and Energy 06 A pendulum of length 50 cm is pulled 30 cm away from the vertical axis and released from rest. What will be its speed at the bottom of its swing? (A) 0.50 m/s (B) 0.79 m/s (C) 1.2 m/s (D) 1.4 m/s Work and Energy 06

  17. Ref: Sec. 6.6-6.7 16 Cons. of Energy Kinetic Energy Potential Energy Work and Energy 06 A 1500-kg car moving at 25 m/s hits an initially uncompressed horizontal spring with spring constant of 2.0 × 106 N/m. What is the maximum compression of the spring? (Neglect the mass of the spring.) (A) 0.17 m (B) 0.34 m (C) 0.51 m (D) 0.68 m Work and Energy 06

  18. Ref: Sec. 6.8-6.9 17 Work/Energy Theorem Work/Friction Kinetic Energy Work and Energy 06 The kinetic friction force between a 60.0-kg object and a horizontal surface is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before coming to a stop? (A) 15.0 m (B) 30.0 m (C) 375 m (D) 750 m Work and Energy 06

  19. Ref: Sec. 6.8-6.9 18 Work/Energy Theorem Work Friction Work and Energy 06 A force of 10 N is applied horizontally to a 2.0-kg mass on a level surface. The coefficient of kinetic friction between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy? (A) 20 J (B) 39 J (C) 46 J (D) 61 J Work and Energy 06

  20. Ref: Sec. 6.10 19 Work/Energy Theorem Power Kinetic Energy Work and Energy 06 A 1500-kg car accelerates from 0 to 25 m/s in 7.0 s. What is the average power delivered by the engine? (1 hp = 746 W) (A) 60 hp (B) 70 hp (C) 80 hp (D) 90 hp Work and Energy 06

  21. END

  22. 01 Work A 500-kg elevator is pulled upward with a constant force of 5500 N for a distance of 50.0 m. What is the net work done on the elevator? F mg Work and Energy 06

  23. 02 Work F q x Matthew pulls his little sister Sarah in a sled on an icy surface (assume no friction), with a force of 60.0 N at an angle of 37.0° upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew? Work and Energy 06

  24. 03 Work Work is the product of force times distance. A force moves an object in the direction of the force. The graph shows the force versus the object's position. Find the work done when the object moves from 0 to 6.0 m. 20 J 40 J 20 J Work is equal to the area under under the curve 80 J Work and Energy 06

  25. 04 Work/Energy Theorem Work A horizontal force of 200 N is applied to move a 55-kg cart (initially at rest) across a 10 m level surface. What is the final kinetic energy of the cart? Work and Energy 06

  26. 05 Work Work/Energy Theorem Kinetic Energy If it takes 50 m to stop a car initially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s under the same condition? Work and Energy 06

  27. 06 Work Work/Energy Theorem Kinetic Energy A spring-driven dart gun propels a 10-g dart. It is cocked by exerting a constant force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has negligible mass? Work and Energy 06

  28. 07 F Work 60 q 80 x A 100-N force has a horizontal component of 80 N and a vertical component of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizontally along the floor. What is the cart's final kinetic energy? Work and Energy 06

  29. 08 Gravitational Potential Energy 15 m 7 m A 15.0-kg object is moved from a height of 7.00 m above a floor to a height of 15.0 m above the floor. What is the change in gravitational potential energy? Work and Energy 06

  30. 09 Gravitational Potential Energy A 400-N box is pushed up an inclined plane. The plane is 4.0 m long and rises 2.0 m. If the plane is frictionless, how much work was done by the push? Work and Energy 06

  31. 10 Spring Potential Energy A spring is characterized by a spring constant of 60 N/m. How much potential energy does it store, when stretched by 1.0 cm? Work and Energy 06

  32. 11 Spring Potential Energy A spring with a spring constant of 15 N/m is initially compressed by 3.0 cm. How much work is required to compress the spring an additional 4.0 cm? Work and Energy 06

  33. 12 Conservation of Energy A skier, of mass 40 kg, pushes off the top of a hill with an initial speed of 4.0 m/s. Neglecting friction, how fast will she be moving after dropping 10 m in elevation? Work and Energy 06

  34. 13 Kinetic Energy Energy Potential Energy v y A 1.0-kg ball falls to the floor. When it is 0.70 m above the floor, its potential energy exactly equals its kinetic energy. How fast is it moving? Work and Energy 06

  35. 14 Cons. of Energy Kinetic Energy Potential Energy A roller coaster starts with a speed of 5.0 m/s at a point 45 m above the bottom of a dip as shown in the diagram. Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip? y1 y2 Work and Energy 06

  36. 15 L H x Cons. of Energy Kinetic Energy y Potential Energy v A pendulum of length 50 cm is pulled 30 cm away from the vertical axis and released from rest. What will be its speed at the bottom of its swing? Work and Energy 06

  37. 16 Cons. of Energy Kinetic Energy Potential Energy A 1500-kg car moving at 25 m/s hits an initially uncompressed horizontal spring with spring constant of 2.0 × 106 N/m. What is the maximum compression of the spring? (Neglect the mass of the spring.) Work and Energy 06

  38. 17 Work/Energy Theorem Work/Friction Kinetic Energy The kinetic friction force between a 60.0-kg object and a horizontal surface is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before coming to a stop? Work and Energy 06

  39. 18 Work/Energy Theorem Work fk F Friction x A force of 10 N is applied horizontally to a 2.0-kg mass on a level surface. The coefficient of kinetic friction between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy? Work and Energy 06

  40. 19 Work/Energy Theorem Power Kinetic Energy A 1500-kg car accelerates from 0 to 25 m/s in 7.0 s. What is the average power delivered by the engine? (1 hp = 746 W) Work and Energy 06

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