A suitcase kept on a shop's rack is measured 50cm×25cm×10cm by shop's owner.

A suitcase kept on a shop's rack is measured $50 \mathrm{~cm} \times 25 \mathrm{~cm} \times 10 \mathrm{~cm}$ by shop's owner. A traveller takes this suitcase in a train moving with a velocity $0.6 \mathrm{c}$. If the suitcase is placed with its length along the train's velocity, find the dimensions measured by

(a) the traveler and

(b) a ground observer.