An Object Is at Rest in the Home Frame $|\beta|=\frac{4}{5}$ With Respect to the Home Frame

Multiple Choice

An object is at rest in the Home Frame. Imagine an Other Frame moving at a speed of $|\beta|=\frac{4}{5}$ with respect to the Home Frame. The object's length in the Other Frame is measured to be $15 \mathrm{~ns}$ . What is its length as observed in the Home Frame?

A) $15 \mathrm{~ns}$
B) $12 \mathrm{~ns}$
C) $9 \mathrm{~ns}$
D) $19 \mathrm{~ns}$
E) 25 ns
F) Other (specify)