That's easy.if the bock goes a distance x then the the change in the total length is 3x.(2x for the string+x for the spring)so the total is 3x.ad there are 2 forces.the spring force +the rod(the one that connects the pulley to block)so the net force is 3T as the tension=force of spring.so the net force on block is 33xk=9kx.and since we displace by x the effective is 9kx/x =9k
–
Spandan Senapati
·
6 months, 2 weeks ago

Log in to reply

@Spandan Senapati
–
but why should the tension be equal to spring force?
–
A E
·
6 months, 2 weeks ago

Log in to reply

@A E
–
In you can think in 2 ways.I)consider the leftmost pulley.I guess its ideal then we can safely consider that the net torque cting on it is zero.which means you are left with fr-Tr=0 implying T=f.or you my thing it as tension will be constant throughout because if we consider the fbd of a small element the net force is zero(as its massless)which means I can extend the same throughout.
–
Spandan Senapati
·
6 months, 2 weeks ago

Log in to reply

@Spandan Senapati
–
Thanks!!!! will you be giving the AITS tomorrow ?
–
A E
·
6 months, 2 weeks ago

hey , sorry please don't bother about options, yes it is asking about some extension,but I think I will be able to solve it myself.But I am not able to understand how is the whole pulley system being replaced by a spring of force constant 9K.
–
A E
·
6 months, 2 weeks ago

Log in to reply

Hey the first 2 options dimensions looks like they are asking for some extensions etc.why don't you repost it with a complete question
–
Spandan Senapati
·
6 months, 2 weeks ago

Log in to reply

What to find.I am not able to get the com question
–
Spandan Senapati
·
6 months, 2 weeks ago

Log in to reply

@Spandan Senapati
–
equivalent spring constant. the answer is given as 9K.
–
A E
·
6 months, 2 weeks ago

## Comments

Sort by:

TopNewestThat's easy.if the bock goes a distance x then the the change in the total length is 3x.(2x for the string+x for the spring)so the total is 3x.ad there are 2 forces.the spring force +the rod(the one that connects the pulley to block)so the net force is 3T as the tension=force of spring.so the net force on block is 3

3xk=9kx.and since we displace by x the effective is 9kx/x =9k – Spandan Senapati · 6 months, 2 weeks agoLog in to reply

– A E · 6 months, 2 weeks ago

but why should the tension be equal to spring force?Log in to reply

– Spandan Senapati · 6 months, 2 weeks ago

In you can think in 2 ways.I)consider the leftmost pulley.I guess its ideal then we can safely consider that the net torque cting on it is zero.which means you are left with fr-Tr=0 implying T=f.or you my thing it as tension will be constant throughout because if we consider the fbd of a small element the net force is zero(as its massless)which means I can extend the same throughout.Log in to reply

– A E · 6 months, 2 weeks ago

Thanks!!!! will you be giving the AITS tomorrow ?Log in to reply

– Spandan Senapati · 6 months, 2 weeks ago

YepLog in to reply

– A E · 6 months, 2 weeks ago

How was the AITS?Log in to reply

– A E · 6 months, 2 weeks ago

Well,then all the best!!Log in to reply

hey , sorry please don't bother about options, yes it is asking about some extension,but I think I will be able to solve it myself.But I am not able to understand how is the whole pulley system being replaced by a spring of force constant 9K. – A E · 6 months, 2 weeks ago

Log in to reply

Hey the first 2 options dimensions looks like they are asking for some extensions etc.why don't you repost it with a complete question – Spandan Senapati · 6 months, 2 weeks ago

Log in to reply

What to find.I am not able to get the com question – Spandan Senapati · 6 months, 2 weeks ago

Log in to reply

– A E · 6 months, 2 weeks ago

equivalent spring constant. the answer is given as 9K.Log in to reply

@Spandan Senapati – A E · 6 months, 2 weeks ago

Log in to reply