A floating ice block moves through a displacement d = (18 ft) i - (22 ft) J, pus
ID: 1551962 • Letter: A
Question
A floating ice block moves through a displacement d = (18 ft) i - (22 ft) J, pushed by a force F (22 lb) i - (17 lb) j on the block. How much work does the force do on the block during the displacement? Note that the displacement is not parallel to the force. The figure shows three forces applied to a trunk that moves 3.0 m leftward over a frictionless floor. The force magnitudes are F_1 - 4.9 N, F_2 = 7.7 N, and F_3 = 5.9 N and the indicated angle is theta = 61 degree. During the displacement, what Is the net work done on the trunk by the three forces?Explanation / Answer
w = F.d
work is scalar product of force and displacement
F = 22 i - 17j
d = 18i -22j
w = 770 ft-lbs
part 5 )
F = -F1i + F2 costhetai + F2 sinthetaj - F3j
F = -4.9 i + 7.7 cos61i + 7.7 sin61j - 5.9j
F = -1.167i + 0.835j
given d = -3i
w = F.d
w = 3.5 J