## College Physics (4th Edition)

We can find the Lorentz factor $\gamma$: $K = (\gamma-1)~m~c^2$ $\gamma = 1+\frac{K}{m~c^2}$ $\gamma = 1+\frac{ 25~MeV}{939.57~MeV}$ $\gamma = 1.0266$ We can find the decay time $\Delta t$ in the lab frame: $\Delta t = \gamma~\Delta t_0$ $\Delta t = (1.0266)(886~s)$ $\Delta t = 910~s$ As measured in the lab, the lifetime is 910 seconds.