The elastic force of the rope when lifting the elevator Fн = 4.0 kn, What work does the elastic force do when the elevator is lifted to a height of h = 20m?
Fн = 4 kN = 4000 N.
h = 20 m.
∠α = 0 °.
A – ?
Mechanical work A is determined by the formula: A = F * S * cosα, where F is the force, S is the movement of the body under the action of the force, ∠α is the angle between the direction of the force F and the displacement S.
When lifting the elevator up, the elastic force of the rope Fн is directed vertically upward.
The movement of the lift S is also directed vertically upwards and is equal to the lift height h.
S = h.
∠α = 0 °, cos0 ° = 1.
A = Fн * h.
A = 4000 N * 20 m = 80,000 J.
Answer: the elastic force of the rope does the work A = 80,000 J.
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