## Mastering Physics Solutions: Blocks in an Elevator Ranking Task

Blocks in an Elevator Ranking Task

Part A = 1.65 * 10^9 J

Solution Below:

Three blocks are stacked on top of each other inside an elevator as shown in the figure. Answer the following questions with reference to the eight forces defined as follows. A. the force of the 3 kg block on the 2 kg block, F3 on 2,
B. the force of the 2 kg block on the 3 kg block, F2 on 3,
C. the force of the 3 kg block on the 1 kg block, F3 on 1,
D. the force of the 1 kg block on the 3 kg block, F1 on 3,
E. the force of the 2 kg block on the 1 kg block, F2 on 1,
F. the force of the 1 kg block on the 2 kg block, F1 on 2,
G. the force of the 1 kg block on the floor, F1 onfloor and
H. the force of the floor on the 1 kg block, Ffloor on 1,

Part A

Assume the elevator is at rest. Rank the magnitude of the forces.
Rank from largest to smallest. To rank items as equivalent, overlap them.

In order from smallest to largest: (C = D) < (A = B) < (E = F) < (G = H)

(C = D) < (A = B) < (E = F) < (G = H)

Part B

Now, assume the elevator is moving upward at increasing speed. Rank the magnitude of the forces.
Rank from largest to smallest. To rank items as equivalent, overlap them.

The answer is the same as in Part A:

In order from smallest to largest: (C = D) < (A = B) < (E = F) < (G = H)

(C = D) < (A = B) < (E = F) < (G = H)

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