Steel train rails are laid in 10m long segments placed end-to-end. The rails are laid on a winter day when the temperature is -10 degrees Celsius. a. if the rails are originally laid in contact, what is the thermal stress on them on a summer day when their temperature is 35 degrees Celsius? b. To prevent thermal stress during summer, what minimum gap between rails must be left when they are originally laid? my answer in (a) is -3.6x10^7 my answer in (b) is 1.8x10^-3 am i correct?