Arope is tied to a box and used to pull the box 2.3 m along a horizontal floor. the rope makes an angle of 30∘ with the horizontal and has a tension of 5 n. the opposing friction force between the box and the floor is 1 n

part a

how much work does gravity do on the box?

part b

how much work does the tension in the rope do on the box?

part c

how much work does the friction do on the box?

part d

how much work does the normal force do on the box?

part e

what is the total work done on the box?

Answered

Explanation:

A) The work done by gravity is zero because displacement and the gravitational force are perpendicular to each other.

W= FS cosθ

θ= 90 ⇒cos90 = 0 ⇒W= 0

B) work done by tension

W= Tcosθ×S= 5cos30×2.30= 10J

C) Work done by friction force

W= f×s=1×2.30= 2.30 J

D) Work done by normal force is Zero because the displacement and the normal force are perpendicular to each other.

E) The net work done= Work done by tension in the rope - frictional work

=10-2.30= 7.7 J

no. dot product   =0 when vecs at right angles