Mufasa roared because of the the fact that, Scars claws were fully extended, while with Simba, hes holding him in a gentle way compared with Mufasa..

Simba was brave and he did not yell

mayb Simba was feeling to much guilt and he was in shock so he didn't notice the pain??

mby muffusa roared because he was suprised scar is his brother afterall and simba knew that scar was evil so he expected to feel some sorta pain

they were jabbed into mufasa more. lol, jabbed!!!

Simbas Father got shocked with the brothers attitude,he did not expect that at all. Wherelse Simba knew his uncles behavior and he knew that one day he would be attacked.by him ofcourse...he is so evil

ok the reason is because yes scars nails not fully out and into simba but if you look carefully scar is holding simba not by the paws but by the arm so it dont hurt that much to be yelling but with Mufasa scar has full nails out but scar for one like digged his nails in to the top of his paws

I guess that simba dint yell because he was shock about how Scar tell their friends that he kill mufasa but simba accep that but Scar continues tell him that he die for his fault an he tell him a lot guilty aswer that wy Scar wen Scar grab is paws dint yell because the pain he as for seen how his father die by his fault he can fell nothing.

Scar was careful with simba because he wanted it to look like he was trying to get him back up because he still wanted the lionesses to like him because even though hes a fully grown malle lion i bet the rest of the 12 lionesses could still kick his ass