Question:

Work and Energy?

A crane lifts a 2.25 x 10^3 N bucket containing 1.15 m^3 of soil to a height of 7.5 mCalculate the work the crane performs.A 845 N sled is pulled a distance of 185 mThe task requires 1.20 x 10^4 J of work and is done by pulling on a rope with a force of 125 NAt what angle is the rope held?Help please, I am so lost, steps?! Thanks!

Answer:

In the first case, the force is applied in the same direction as movement; work is simply force times distance moved: (2.25 x 10^3 N)(7.5 m) 16875 J In the second case, you can find the component of force in the direction of movement by dividing work done by distance moved: (1.20 x 10^4 J) / (185 m) 64.86 N To find the angle of the rope, draw a right triangle representing the force vectorsThe hypotenuse is the applied force equal to 125 NThe horizontal base is 64.86 NUse trig to find the angle: cos(theta) (64.86 N)/(125 N) theta 58.74 degrees

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