Work

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Across
  1. 2. If 6 J of work is needed to stretch a spring from 10 cm to 12 cm and another 10 J is needed to stretch it from 12 cm to 14 cm, what is the natural length of the spring?
  2. 4. When a particle is located a distance x meters from the origin, a force of cos(pix/3) newtons acts on it. How much work is done in moving the particle from x − 1 to x − 2? Interpret your answer by considering the work done from x − 1 to x − 1.5 and from x − 1.5 to x − 2.
  3. 6. An aquarium 2 m long, 1 m wide, and 1 m deep is full of water. Find the work needed to pump half of the water out of the aquarium. (Use the fact that the density of water is 1000 kg/m^3.)
  4. 8. A 360-lb gorilla climbs a tree to a height of 20 ft. Find the work done if the gorilla reaches that height in 10 seconds.
  5. 9. A 10 ft chain weights 25 lb and hangs from a ceiling. Find the work done in lifting the lower end of the chain to the ceiling so that it is level with the upper end.
Down
  1. 1. How much work is done when a hoist lifts a 200-kg rock to a height of 3 m?
  2. 3. A 360-lb gorilla climbs a tree to a height of 20 ft. Find the work done if the gorilla reaches that height in 5 seconds.
  3. 5. A thick cable, 60 ft long and weighing 180 lb, hangs from a winch on a crane. Compute the work done if the winch winds up 25ft of the cable.
  4. 7. A chain lying on the ground is 10m long and its mass is 80 kg. How much work is required to raise one end of the chain to a height of 6m.