Question:medium

In a hydraulic lift force F is applied to balance 10 N load, diameter of effort arm is 14 cm and load arm is 1.4 cm. The F is equal to

Updated On: Mar 19, 2026
  • 500 N
  • 100 N
  • 2000 N
  • 1000 N
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The Correct Option is D

Solution and Explanation

To solve this problem, we need to understand how a hydraulic lift works. A hydraulic lift multiplies the force applied using Pascal's principle, which states that pressure applied to a confined fluid is transmitted undiminished in all directions throughout the fluid, regardless of the area over which it was applied.

Given in the problem:

  • Force required to balance the load, \( F_{\text{load}} = 10 \, \text{N} \)
  • Diameter of the effort arm, \( d_{\text{effort}} = 14 \, \text{cm} \)
  • Diameter of the load arm, \( d_{\text{load}} = 1.4 \, \text{cm} \)

The force applied at the effort arm is balanced by the load at the load arm through the hydraulic lift, which can be expressed by the formula for hydraulic systems:

F_{\text{effort}} \cdot A_{\text{effort}} = F_{\text{load}} \cdot A_{\text{load}}

where:

  • \( A_{\text{effort}} \) is the area of the effort piston
  • \( A_{\text{load}} \) is the area of the load piston

Assuming both pistons have circular cross-sections, we can use the formula for the area of a circle \( A = \frac{\pi d^2}{4} \). Therefore,

A_{\text{effort}} = \frac{\pi (d_{\text{effort}})^2}{4}

A_{\text{load}} = \frac{\pi (d_{\text{load}})^2}{4}

Substitute \( A_{\text{effort}} \) and \( A_{\text{load}} \) into the original formula, we get:

F_{\text{effort}} \cdot \frac{\pi (d_{\text{effort}})^2}{4} = 10 \cdot \frac{\pi (d_{\text{load}})^2}{4}

By cancelling the common terms and rearranging for \( F_{\text{effort}} \), we have:

F_{\text{effort}} = 10 \cdot \left(\frac{d_{\text{load}}}{d_{\text{effort}}}\right)^2

Substitute the given values:

F_{\text{effort}} = 10 \cdot \left(\frac{1.4}{14}\right)^2

Calculate the above expression:

F_{\text{effort}} = 10 \cdot \left(\frac{1}{10}\right)^2

F_{\text{effort}} = 10 \cdot \frac{1}{100}

F_{\text{effort}} = 1000 \, \text{N}

Thus, the force \( F \) needed to balance the hydraulic system is 1000 N, which is the correct answer.

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