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Home Q & A Board Science-Related Homework Help Physics
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ac_1992 ac_1992
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11 years ago
A fly has a mass of 0.50 gram at rest. How fast would it have to be traveling to have the mass of a large SUV, which is about 2500 kilograms?
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wrote...
#1
11 years ago
USE: Mass = 1/SQRT(1 - (v/c)^2).
wrote...
#2
11 years ago
Here's an example:

Sample Question
How fast would the fly have to be traveling to have the mass of a large SUV, which is about 3000 kilograms? A fly has a mass of 1.50 gram at rest.

Answer
Special relativity puts the relativistic mass to be the rest mass factored by "gamma", with gamme being 1/SQRT(1 - (v/c)^2).

You want a ratio of 3000000 to 1.5, or 2 million to 1.

2E6 = 1/SQRT(1 - (v/c)^2)
1 - (v/c)^2 = (0.0000005)^2
0.99999999999975 = (v/c)^2
0.999999999999875 = v/c
v= 99.9999999999875% of the speed of light.
Using the value for c, we thus have a speed of 299792457.99996 m/s, or only 0.00004 m/s slower than the speed of light.
wrote...
#3
11 years ago
Use this formula:

Mass = Rest mass / sqrt( 1 - v^2 / c^2 )
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