Across
- 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?
- 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.
- 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.)
- 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.
- 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. How much work is done when a hoist lifts a 200-kg rock to a height of 3 m?
- 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.
- 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.
- 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.