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I don't think Newtonian physics accounts for time dilation or mass change with velocity.

Those didn't come up until Einstein.

Of course Newton worked out how mass changes with velocity.

We still use this formula today , since his day we have refined

the exact calculation in what defines a kilogram of mass to determine gravitational mass in his gravitational constant

, but this formula is unchanged.

Force= mass x acceleration or F=ma

and

g = 9.80665 m/s2

Trivia ...

"Since 1889, the kilogram has been defined as the mass of the international prototype kilogram, and as such is independent of the meter, or the properties of water. In October 2011, the 24th General Conference on Weights and Measures resolved to "take note of the intention" to redefine the kilogram in terms of the Planck constant, scheduled for 2014."

http://en.wikipedia.org/wiki/Mass

Time dilation is realization of special relativity and GR which deals in velocity far past Newtons thoughts as well as the concept of space/time that newton viewed as separate dimensions.

Where Einstein wove them together.

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