Learning Goal:
To understand the concept of moment of a force and how to calculate it using a vector formulation.
A man wishes to spin a merry-go-round in the x–y plane centered at the origin (0.000,0.000,0.000)
. (Figure 1) Because he must pull upward and cannot stand on the merry-go-round, he must apply a force in the direction of the unit vector u=(−1/3)i+(2/3)j+(2/3)k
. He pulls with a force F
= 43.0 lb
from point A [(3.00,4.00,0.000)
ft
].
Figure1 of 1
The figure shows a merry-go-round in the xyz-space. The z-axis is directed upward and coincides with the rotational axis of the merry-go-round. A person applies force F to the merry-go-round at point A. Vector r points from the origin to point A.
Part A
What are the x, y, and z components of the resulting moment acting on the merry-go-round about the origin?
Express your answers numerically in pound-feet to three significant figures separated by commas.
Mx
, My
, Mz
=