34) This question asks us to find the mass of the plank given that we know different positions of a person, box, and the plank. The diagram in the question defines the zero point as the point where the box is placed. We can use this zero-point to solve for the center of mass before the person starts walking.
The value of x[plank,i] is the position of the center of mass of the plank. We can solve for the center of mass of the entire system.
After the person moves, the person and box are at the end of the plank, but the plank has moved 3.84 meters to the right. We can solve for the center of mass of the system after the person has moved.
Since there are no external forces acting on the person-box-plank-system, we know that the center of mass is constant. This means we can equate the initial and final center of mass to solve for the mass of the plank.
Answer: C
Comments