Third Order Lever Problem

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In summary, the conversation discusses a hydraulic lifting beam with 200kg crates and various calculations related to it. The order of lever used is third order, and the effort required to lift the load is calculated to be 1200N. The mechanical advantage of the system is 0.16, and the velocity ratio is calculated to be 0.01666. The efficiency of the system is 65%. The question of whether to assume 100% efficiency leads to using the equation for velocity ratio based on distances moved by effort and load, but the distances are not given. The force load may actually be 1962N due to the effects of gravity, and the displacement for effort may be 5 times the distance from the load
  • #1
junkie_ball
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Homework Statement



The 200Kg Crates are placed on a hydraulic lifting beam: (Diagram attached)

A. State the order of lever used here
B. Calculate the effort required to lift the load
C. Calculate mechanical advantage for this system
D. Calculate the velocity ratio for this system. If the work put in is 3000J.Calculate the useful energy output.
E. System has efficiency of 65%. Calculate the velocity ratio for this system.

Homework Equations

Effort Required = large distance x small effort = small distance x large load

Mechanical advantage = load/effort

Velocity ratio = distance moved by effort/distance moved by load OR
Velocity ratio = Mechanical Advantage/Efficiency

Efficiency = output/input

Efficiency = mechanical advantage/velocity ratio

The Attempt at a Solution



A. Third Order as the effort lies between to the fulcrum and load

B. Force Effort (Fe) x Distance Effort (De) = Force Load (Fl) x Distance Load (Dl)

Fe = (Fl x Dl)/De
Fe = (200 x 6)/1
Fe = 1200N

C. Mechanical Advantage (Ma) = Load / Effort

Ma = 200/1200
Ma = 0.16 Recurring

D. This is where i have become slightly confused do i assume the system is 100% efficient for this part of the question? In which case i could use the following to calculate the valocity ratio

Velocity ratio (Vr) = Mechanical Advantage (Ma) /Efficiency (E)
Vr = 0.16/100
Vr = 0.01666 (THIS SEEMS INCORRECT TO ME)

As such the equation Velocity ratio = distance moved by effort/distance moved by load would be the one to use. The problem is i have not been given the distances moved. I know i need to take the work put in somehow to get my answer but not sure how to use this. Could someone please point me in the right direction?

E. I will calculate this once I've solved for part D
 

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  • #2
Hi,

I guess i worded this question wrong. Anyway have spend some more time on it and now have a slightly different question for this system. The force load is 200KG but as there is gravity acting on the crate will the force load be (200 x 9.81) making it 1962N rather than 200N?

I have now figured out how to use the work put into calculate the displacement. One last question as the effort displacement is 5m from the load effort will the displacement be 5x larger or is it 6x as this is the distance from the fulcrum. I believe it will be 5x?
 

1. What is a third order lever problem?

A third order lever problem is a type of problem in mechanics and physics that involves a lever with three points of contact - a fulcrum, an effort force, and a resistance force. The lever is used to amplify the effort force in order to move or lift a resistance force.

2. How do you determine the mechanical advantage of a third order lever?

To determine the mechanical advantage of a third order lever, you need to first find the distance between the fulcrum and the effort force (called the effort arm) and the distance between the fulcrum and the resistance force (called the resistance arm). Then, divide the effort arm by the resistance arm to calculate the mechanical advantage.

3. What is the equation for calculating the output force of a third order lever problem?

The equation for calculating the output force of a third order lever problem is: Output force = (Resistance arm / Effort arm) * Input force. This equation takes into account the mechanical advantage of the lever in amplifying the input force to overcome the resistance force.

4. Can a third order lever have a mechanical advantage greater than 1?

Yes, a third order lever can have a mechanical advantage greater than 1. This means that the output force will be greater than the input force, allowing the lever to lift or move heavier loads with less effort.

5. What are some real-life examples of third order lever problems?

Some real-life examples of third order lever problems include using a crowbar to lift a heavy object, using a wheelbarrow to move a load, and using a shovel to lift and move dirt. In all of these situations, the lever is used to amplify the effort force and overcome the resistance force.

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