A man whose mass is 80kg climbs a staircase in 20s and expends power of 120W. Find the height of the staircase.[g = 10ms-2]
A
1.8m
B
2.0m
C
2.5m
D
3.0m
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Power x time = mgh
120 x 20 = 80 x 10 x h
2400 = 800h
making h the subject of formula,divide both side by 800
\(\frac{2400}{800}\) = h
h = 3m
Source: Myschool Past Questions Archive (Record #27603)