Ali's office is on the ground floor of a research center.  He takes an elevator to get to the third floor. His velocity versus time graph in the elevator is shown in the figure. If his mass is 60kg calculate his weight at i) t = 2 s, ii) t = 5 s, and iii) t = 7 s.

• A. i) 708 N, ii) 588 N, iii) 408 N
• B. i) 708 N, ii) 684 N, iii) 348 N
• C. i) 645 N, ii) 455 N, iii) 408 N
• D. i) 708 N, ii) 588 N, iii) 309 N

Answer: (A)