13. the graph below represents the journey of a steam train. the vertical axis represents the distance from the station in kilometers.
a. how far did the train travel in first 40 minutes?
b. work out the speed of the train between a and b. give your answers in kilometers per hour.

In a heat engine of 1000 j of heat enters the system and the piston does 500 j of work what is the final internal energy of the system if the inital energy was 2000 j we have to do all of these down here 1)write the equation 2)list out your know variables 3)plug the numbers into the equations 4)solve 5)write your solution statemtn that includes inital energuy and final energuy added