Doing things differently

Poor Durga Prasad, my friend and office colleague and who resides just in the flat beneath mine has lost his ID card. Its actually misplaced, and a team mate sneaked to play a prank on him. While going home, he deposited the card with me asking me to give it to DP when I go home. I hinted DP that his card is not lost and is safe at one of the team member and he needn't panic. However, I didn't leak the name with whom it is, instead I asked another fellow team mate to mail him the following 3 hinting puzzles, whose answer words when arranged in a fashion would give him an idea as to who holds the card presently. It was fun designing the puzzle. Here I'd like to copy paste the mail sent a few hours back to his mail box

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Solve the puzzle(s) to get hints for your id card.

Hint1: I as you call?
Hint2: arrange the letters to form a meaningful English word - S I E R D E
Hint3: if two freely falling bodies having masses m1=10.227kg and m2=4.773kg start in air simultaneously at 900m above the ground but with different initial velocities u1=2.36m/s and u2=2.18m/s. After t=6.684 seconds, m1 is ______ m2.

Arrange answers for the three hints to get a master hint, solving which you would get to know which person has your id card.

Thanks
Your well wisher
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Master hint should be
YOU RESIDE BELOW? which would hint that I have his ID card

There is a purpose for this blog, beyond sharing the experiment and that is... in case he couldn't solve the 3 puzzles I'll design another vague hinting to this blog (rather easy one this time).

Jaya