Friday

September 19, 2014

September 19, 2014

Posted by **Jessica** on Monday, March 31, 2008 at 3:30am.

I know to use the Work integral, but im not sure wat equation to use

- physics/calc -
**drwls**, Monday, March 31, 2008 at 5:35amThe 500 lb bucket of cement is raised 30 ft. That part of the work required is 500x30 = 15,000 ft-lb. A 75 ft length of rope weighing 75/2 = 37.5 lb has its center of mass raised from 75/2 = 37.5 ft elevation to a situation where 30 feet is at 75 ft elevation, and a 45 feet length has a center of mass at (75+30/2) =52.5 ft. The potential energy increase of the rope is [15*37.5 + 22.5*52.5 - 37.5*37.5]= 337.5 ft lb

The total work required is 15,337.5 ft-lb

**Answer this Question**

**Related Questions**

Calc II - A worker on scaffolding 65 ft above the ground needs to lift a 390 lb ...

Physics - A skateboarder shoots off a ramp with a velocity of 6.8 m/s, directed ...

Physics - A roller-coaster car with a mass of 500 kg starts at rest from point A...

Physics - A model rocket has a mass of 3.00 kg. It is fired so that when it is ...

physics - a child drops a toy at rest from a point 4m above the ground at the ...

physics - A 2 kg brick is accidentally dropped off some scaffolding from a ...

calculus - A bridge worker on the top deck of a double decked bridge needs to ...

Physics - The Falling Paint Can: A painter is standing on scaffolding that is ...

Physics - A skateboarder shoots off a ramp with a velocity of 5.7 m/s, directed ...

Physics - A skateboarder shoots off a ramp with a velocity of 6.5 m/s, directed ...