Laws Of Motion Question 256
Question: With what minimum acceleration can a fireman slides down a rope while breaking strength of the rope is $ \frac{2}{3} $ of his weight[CPMT 1979]
Options:
A) $ \frac{2}{3}g $
B) g
C) $ \frac{1}{3}g $
D) Zero
Show Answer
Answer:
Correct Answer: C
Solution:
If man slides down with some acceleration then its apparent weight decreases. For critical condition rope can bear only 2/3 of his weight. If a is the minimum acceleration then, Tension in the rope $ =m(g-a) $ = Breaking strength therefore $ m(g-a)=\frac{2}{3}mg $ therefore$ a=g-\frac{2g}{3}=\frac{g}{3} $
