Motion

The nucleus of a helium atom travels along the inside of a straight hollow tube \(4 \mathrm{~m}\) long which forms part of a particle accelerator. If one assumes uniform acceleration, how long is the particle in the tube if it enters at a speed of \(2000 \mathrm{~m} / \mathrm{s}\) and leaves at \(8000 \mathrm{~m} / \mathrm{s}\)