Verification of the law of parallelogram of forces

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Verification of the law of parallelogram of forces and

hence determination of the weight of a given body

Verification of the law of parallelogram of forces and hence determination

of the weight of a given body

Learning outcomes

• Takes remedial measures to eliminate any defects such as friction in the pulleys

of the parallelogram of forces apparatus, and uses the apparatus appropriately.

• Checks practically the correctness of the equilibrium position obtained

• Marks correctly the perpendicular projection of strings on the paper by using the

supplied devices.

• Verifies the law of parallelogram of forces and determines the weight of a given

object using the parallelogram of forces apparatus.

Materials and equipments

A parallelogram of forces apparatus, an object of unknown weight (w), three

weights of known values (w1. w2. w3), a set square or a short strip of a plane

mirror, a half metre ruler, four drawing pins, a white sheet of paper ( A 4).

Teaching instructions

• Check the parallelogram of forces apparatus for defects such as friction in the

pulleys and give instructions on eliminating them.

• Give instructions as to how to check the accuracy of the equilibrium position

after obtaining it.

• Check the ways of obtaining perpendicular projections of strings and provide

necessary instructions.

Video Lecture in Hindi with Englsih subtitles on the theory behind the Experiment with Gravesand's Apparatus using Law of Parallelogram of forces by an IITian.