A box rests on a horizontal, frictionless surface. a girl pushes on the box with a force of 17 n to the right and a boy pushes on the box with a force of 13 n to the left. the box moves 3.5 m to the right. find the work done by (a) the girl, (b) the boy, and (c) the net force.

Question

Physics

August Nixon

4 May, 11:27

A box rests on a horizontal, frictionless surface. a girl pushes on the box with a force of 17 n to the right and a boy pushes on the box with a force of 13 n to the left. the box moves 3.5 m to the right. find the work done by (a) the girl, (b) the boy, and (c) the net force.

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Answers (1)

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Frances Haas · Answer 1

Refer to the diagram shown below.

The net force acting on the box is 17 - 13 = 4 N to the right.

The box moves on a friction surface by 3.5 m to the right.

By definition,

Work = Force x Distance.

(a) The work done by the girl is

W₁ = (17 N) * (3.5 m) = 59.5 J

(b) The work done by the boy is

W₂ = (13 N) * (-3.5 m) = - 45.5 J

(c) The work done by the net force is

W₃ = (4 N) * (3.5 m) = 14 J

Note that W₃ = W₁ + W₂

Answers:

(a) 59.5 J

(b) - 45.5 J

(c) 14 J