Question
A man of mass 50 kg ascends 30 steps of a staircase in 15 seconds. If the height of each step of the staircase is 20 cm, find the power of the man (g = 9.8 m/s2). [Ans. 196 W]
Answer
Mass (m) = 50 kg
Height (h) = 30 × 20 cm = 6 m
Time (t) = 15 s
Step 1: Calculation of work
Work (W) = mgh
= 50 × 9.8 × 6 = 2940 J
Step 2: Calculation of Power
Power (P) = Work\over Time
= 2940\over 15 = 196 W