CORNERSTONE:
Engineers must decide how to move the
cornerstone of a pyramid 800 feet across the foundation. Each ox can apply 120 pounds force of traction and up to 28 can be teamed. The foundation is compacted flat and with rollers will have a coefficient of friction, μ, of about 0.1. In addition a 40-man lifting harness is available (Men can lift 70 pounds, thereby reducing the normal force).
OXEN: Can the oxen place the stone without assistance from men? Analysis to the right shows 30 oxen would be needed. Oxen cannot move the stone unassisted.
OXEN AND MEN: Analysis to the right shows 32 men must assist the oxen. The engineer decides to "fill" the lifting harness. He commits 40 men to the task. What load must each oxen pull?