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View Full Version : Is this physic question right?


rukai2
May 3, 2011, 11:36 AM
A - 1kg meter stick (100 cm) is supported at the 70 cm mark. A 2-kg mass hangs from it at the 80-cm mark. What is the position at which one would hang a 4 kg mass to keep the stick balanced? _______cm mark

= 100

ebaines
May 3, 2011, 12:59 PM
No, incorect answer.

To do this you want the moments about the support point due to the two weights to cancel out. The moment of each weight is equal to its mass times the distance from the support point. The second 4 Kg weight weighs twice as much as the 2 Kg weight, so it needs to be half the distance from the support point as the 2 Kg weight. Can you solve this now?