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Home Engineering Mechanics Electrical Machines To verify the law of moments using a bell crank lever.
Electrical Machines Lab Experiments

To verify the law of moments using a bell crank lever.



Aim

To verify the law of moments using a bell crank lever.

Theory:

This experiment is based on the basic engineering principle i.e., the Principle of Moments. The algebraic sum of moments of all forces about any point is equal to the moment of the resultant about same point.

apparatus

Apparatus Used:

  1. Bell crank lever
  2. Sets of weights
  3. Sprit level
  4. Meter scale

Procedure:

  1. Note down the initial reading of the spring balance when no load is applied.
  2. Apply suitable load W on the arm.
  3. Measure distance on the scale from the fulcrum.
  4. Note down the reading of the spring balance T in equilibrium.
  5. Measure vertical distance.
  6. Repeat the same process for different loads.

Observations and Calculations:

Length of arm d1 =…………………………..

Radius of flywheel axle (r) =……….cm

S.no Load on lever/W Length of side/d2 Spring balance reading/initial (S1)/Final (S2)/T= S2 – S1 Moments/M2 = W d2/M1 = W d1 Percentage error = M1 –M2 /M1 X100
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Result:The average percentage error is =……………………

Precautions:

  1. Weight should not be applied with any jerk.
  2. Measure distance carefully from fulcrum.
  3. Lever arm should horizontal before taking the reading.

Viva Questions:

Q1. Define lever?

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Q.2. Draw the free body diagram of lever?

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Q.3. What is a bell crank lever?

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Q. 4. What is the leverage?

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Q.5 Give the example of lever commonly used in our daily life?

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Q.6Explain the principle of lever.

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Q.7 State the law of moments.

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Q.8 What is Varignon`s principle?

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