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
Correct Answer: Option D
Explanation
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