The two ropes seen in the figure are used to lower a 255 kg piano 5.90 from a second-story window to the grou?

if you find the vertical components of the tensions in the ropes (1830 sin 60 and 1295 sin 45), you will see they equal the weight of the piano, so that the piano is being lowered at a constant speed (with no accleration)

the work done by a force is force in the direction of motion x displacement

so the work done by the ropes is - T sin(theta) x 5.9m

T sin(theta) is the vertical component of force, 5.9m is the distance, and the minus sign indicates that the force (due to the ropes) is opposite the direction of motion

the work done by gravity is simply 2500N x 5.9m and is positive since the force is in the direction of motion

W1 = - 1830 sin 60 x 5.9m

W2 = - 1295 sin 45 x 5.9m

W3 = 2500N x 5.9m

i'm figuring your drawing Wg = is the burden of the piano = 255 ( 9.80 one ) = 2501.55 Newtons the two forces of ropes are W1 and W2 . . . that are equivalent . . say W 2 W = 2501.55 W = 2501.55 / 2 = 1250.775 Newtons . . . tension on each and every rope