- #1
Vibhor
- 971
- 40
Hello ,
Please see the attached image , in first case thread A is pulled with gradually increasing force while in second case an impulsive force is applied on thread A ? Which one breaks first in the two cases ?
I think in the first case , thread B breaks . In second case , thread A breaks first .
This is my reasoning -
Consider the mass and apply Newton's II law to it .Downwards is taken positive .
∑F = ma
FA - FB + mg = ma
FA - FB = m(a-g)
Case 1 ) When the thread is pulled slowly, acceleration 'a' would be negligible and we get ,
FA - FB = -mg < 0
FA < FB
Hence B breaks first .
Case 2) But if A is pulled very fast than 'a' would be very large and we get ,
FA - FB = m(a-g) >0 . Now here I am assuming that 'a' > g ( Is this correct ??)
FA > FB
Hence A breaks first .
Is the above reasoning correct ? I am a little unsure in Case 2) where I am considering 'a' to be very large when the sudden force is applied on thread A . Is it right to take 'a' very large ??
Many Thanks
Please see the attached image , in first case thread A is pulled with gradually increasing force while in second case an impulsive force is applied on thread A ? Which one breaks first in the two cases ?
I think in the first case , thread B breaks . In second case , thread A breaks first .
This is my reasoning -
Consider the mass and apply Newton's II law to it .Downwards is taken positive .
∑F = ma
FA - FB + mg = ma
FA - FB = m(a-g)
Case 1 ) When the thread is pulled slowly, acceleration 'a' would be negligible and we get ,
FA - FB = -mg < 0
FA < FB
Hence B breaks first .
Case 2) But if A is pulled very fast than 'a' would be very large and we get ,
FA - FB = m(a-g) >0 . Now here I am assuming that 'a' > g ( Is this correct ??)
FA > FB
Hence A breaks first .
Is the above reasoning correct ? I am a little unsure in Case 2) where I am considering 'a' to be very large when the sudden force is applied on thread A . Is it right to take 'a' very large ??
Many Thanks