Answer:
C. The net work done by the two forces is zero joules.
Explanation:
Work (W) is defined as the product of force F) by the distance (d)the body travels due to this force.
W= F*d Formula ( 1)
The work is positive (W+) if the force has the same direction of movement of the object.
The work is negative (W-) if the force has the opposite direction of the movement of the object.
The component of the force that performs work must be parallel to the displacement.
Calculation of the forces
We apply Newton's second law:
∑F = m*a
∑F : algebraic sum of the forces in Newton (N)
m : mass in kilograms (kg)
a : acceleration in meters over second square (m/s²)
∑F = m*a
a = 0 because the elevator moves at constant speed.
∑F=0
T-W = 0
T = W
Calculation of work done by the forces
W₁ : work done by the gravity= (+ W*d ) J
W₂ : work done by the tension force=( -T*d) J
Net work done by the two forces(W₁-W₂):
W₁= W₂ .because T = W
W₁-W₂ =0
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