Question
A mountain 10.0 km from a person exerts a gravitational force on him equal to 2.00% of his weight. (a) Calculate the mass of the mountain. (b) Compare the mountain's mass with that of Earth. (c) What is unreasonable about these results? (d) Which premises are unreasonable or inconsistent? (Note that accurate gravitational measurements can easily detect the effect of nearby mountains and variations in local geology.)
1. $2.9\times 10^{17}\textrm{ kg}$
2. $4.9\times 10^{-8}$
3. Mountains are just fuzz on a massive planet. For any single mountain to comprise a significant fraction of the Earth's mass us unreasonable.
4. The gravitational force is not 2.00% of the person's weight.
Solution Video