A moral dilemma

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watched a ted talk the other night....

it was by a guy called Michael sandel. in it he asked what would you do in a given situation;
you were on a trolley train (a small maintenance vehicles used to check the track) that was going to plow into five people on the track and kill them, up ahead was a fork that sent you away from the five but in doing killed a single person on the other track. what would you do. we all said kill the one. the answer was easy
another question was. if you were overlooking the scene and knew by pushing the fat gut next to you, into the path of the trolley train you'd save the five people, though the fat guy would def die. would you push off the bridge? the answer to this one wasn't as straight forward. people hummed and were less outspoken as to what they'd do.

so it got me thinking;

if a person pulls a knife on a stranger for no reason other than to rob him, he sticks the guy with it, the guy faints, but doesn't die after being stabbed and is robbed by the knife-man. later the knife-man is caught and convicted of attempted murder and sentenced to 15 year in prison. a week later another knife-man does the same thing except this time the knifes goes into an apple in the victims pocket. the victim faints as did the first one but more from fear than being stabbed (the knife never touched him). again the knife-man robs his victim and is later caught. the moral question is this. should the second knife-man get the same sentence as the first knife-man?

if yes, why
if no, why not? weren't they both the same crime?