A car accelerates from rest to u m / s. The energy spent in this process is E J. The energy required to accelerate the car from u m / s to 2 u m / s…

A car accelerates from rest to $\displaystyle \mathrm{u} \mathrm{m} / \mathrm{s}$. The energy spent in this process is E J . The energy required to accelerate the car from $\displaystyle \mathrm{u} \mathrm{m} / \mathrm{s}$ to $\displaystyle 2 \mathrm{u} \mathrm{m} / \mathrm{s}$ is nE J. The value of n is $\displaystyle \_\_\_\_$.