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anonymous
 one year ago
A block and tackle is used to raise a 72.0 N crate 12.3 m from the loading dock to the ship. This requires a force of 25.0 N to be applied by the longshoreman.
Part 1: What is the mechanical advantage of the block and tackle?
Part 2: How much rope must be pulled? Note: Assume that IMA = MA.
Part 3: The longshoremen have only a 40 m rope that they are told not to cut. They use this for the block and tackle. How does this affect the efficiency of the block and tackle?
**how do we solve these? :/ thanks @Michele_Laino !!:)
anonymous
 one year ago
A block and tackle is used to raise a 72.0 N crate 12.3 m from the loading dock to the ship. This requires a force of 25.0 N to be applied by the longshoreman. Part 1: What is the mechanical advantage of the block and tackle? Part 2: How much rope must be pulled? Note: Assume that IMA = MA. Part 3: The longshoremen have only a 40 m rope that they are told not to cut. They use this for the block and tackle. How does this affect the efficiency of the block and tackle? **how do we solve these? :/ thanks @Michele_Laino !!:)

This Question is Closed

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1part 1 the requested advantage is given by the subsequent ratio: \[\large R = \frac{{72}}{{25}}\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh okay! so we get 2.88 is the requested mechanical advantage?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1yes! Whereas the efficiency E, of our machine, is: \[\Large E = \frac{{25}}{{72}} = ...\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ohh okay! it is 0.347222....

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1no, it is an additional information only. Our answer, to part 1 is 2.88

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh ok! so we do not need to include the efficiency? just the 2.88 mechanical advantage?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okie! so onto part 2!

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1for part #2, if I call with L the length of the pulled rope, then we can write: \[\large 72 \times 12.3 = 25 \times L\]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1so we have: \[\Large L = \frac{{72 \times 12.3}}{{25}} = ...meters\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so is that the amount of how much rope must be pulled? 35.424 m?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok! yay!! so onto part 3?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1if we have to pull 40 meters of rope, then the force F applied by the longshoremen, is: \[\Large F = \frac{{72 \times 12.3}}{{40}} = ...Newtons\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok! so we get 22.14 Newtons! is that our solution for part 3?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh wait, that is just the force, right? how can we find the efficiency?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1the new advantage is: \[\Large R = \frac{{72}}{{22.14}} = ...\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0or how can we find how it affects the efficiency?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1whereas the new efficiency, is: \[\Large E = \frac{{22.14}}{{72}} = ...\]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1I think that your problem asks for efficiency, also in part #1

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok! so we get 0.3075 is the efficiency? and i think we don't need it for part 1? since it asks for mechanical advantage only? or do we need to include the efficiency we calculated earlier for part 1?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1so the answer to part #1 is: \[\Large E = \frac{{25}}{{72}} \cong 0.35\]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1that's right! the new efficiency is: \[\Large E = \frac{{22.14}}{{72}} \cong 0.31\]

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1namely the efficiency will decrease

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yes:) and yay!! so that is how it affects efficiency? it will decrease?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yay! thanks!! so we are done?

Michele_Laino
 one year ago
Best ResponseYou've already chosen the best response.1yes! we have finished!

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yay!! ok! onto the next!!:)
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