Work Energy And Power Question 178
Question: A man is riding on a cycle with velocity 7.2 km/hr up a hill having a slope 1 in 20. The total mass of the man and cycle is 100 kg. The power of the man is
Options:
A) 200 W
B) 175 W
C) 125 W
D) 98 W
Show Answer
Answer:
Correct Answer: D
Solution:
$ v=7.2\frac{km}{h}=7.2\times \frac{5}{18}=2\ m/s $
Slope is given 1 in 20 \ $ \sin \theta =\frac{1}{20} $
When man and cycle moves up then component of weight opposes it motion i.e. $ F=mg\sin \theta $
So power of the man $ P=F\times v $
$ =mg\sin \theta \times v $ = $ 100\times 9.8\times ( \frac{1}{20} )\times 2=98\ Watt $
