A 4.0-kilogram rock and a 1.0-kilogram stone fall freely from rest from a height of 100 meters. After they fall for 2.0 seconds, the ratio of the rock’s speed to the stone’s speed is

(1) 1:1 (3) 2:1

(2) 1:2 (4) 4:1

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- Jan 19th 2007, 06:46 PMsymmetryRock's Ratio
A 4.0-kilogram rock and a 1.0-kilogram stone fall freely from rest from a height of 100 meters. After they fall for 2.0 seconds, the ratio of the rock’s speed to the stone’s speed is

(1) 1:1 (3) 2:1

(2) 1:2 (4) 4:1 - Jan 19th 2007, 11:27 PMAfterShock
If I'm not mistaken, the free fall is v = g*t, where g = 9.8 m/s/s, thus we'll round to 10.

It has nothing to do with the weight of the object, and thus they both fall at the same velocity. Therefore, the answer is (1).

Objects that are in free-fall move under the influence of gravity alone; they do not experience air-resistance. More massive objects will not fall faster, unless there is a significant amount of air resistance. In summary, all objects that are in free-fall will have the same rate of acceleration, regardless of taking their mass into account. Topsquark can probably elaborate far more than I can on this physics question. - Jan 20th 2007, 12:21 AMCaptainBlack
- Jan 20th 2007, 04:50 AMsymmetryok
So, two objects of different mass falling to earth at the same time is possible if air resistance is applied.

Very interesting concept. - Jan 21st 2007, 03:19 AManthmoo
- Jan 21st 2007, 04:12 AMtopsquark