# The crane lifts the girder to a height of 20 m, the girder weight is 10 kN. Calculate the work done by the crane.

July 26, 2021 | education

| The beam lifted to a height of 20 m is acted upon by the force of gravity F = gm and the tension force of the cable-elastic force. The work is performed by an elastic force that coincides in direction with the movement of the beam and is equal in modulus to the force of gravity.

Work A = F * h, where h is displacement to a height of 20 m, and F is the elastic force: A = gmh.

A = 9.8 N / kg * 10,000 N * 20 m = 1,960,000 J = 19.6 * 10 ^ 5 J = 1.96 kJ.

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