 Solution

ID: past-exam-of-the-short-options-course-of-the-university-of-oxford/2014/7/b/ii/solution

Since

s

A = \frac{d U}{d s} = c ω (sinh ω s, cosh ω s, 0, 0) .

Its Minkowski norm squared is

g (A, A) = - c^{2} ω^{2}

, so the invariant magnitude of proper acceleration is

- g (A, A) = c ω .

The vector is spacelike, which accounts for the minus sign under the square root.

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