why cant we plug in the initial velocity for the kinetic energy and equate that to the spring energy? shouldnt they be the same since energy is conserved?
because in the final state (the moment of max compression) the masses are still moving, so some of the energy will be in the translational kinetic energy of the masses; i.e., not all the initial energy is in the compression of the spring. z
I've noticed a lot of traffic coming from India lately -- I wonder if it would be helpful to close caption my videos for Indian audiences. If I did that, what do you think the most important languages would be? It's also possible the auto-translating in UA-cam isn't good enough to bother with. Interested to hear what you think. -- Zak
If the block on the left is moving faster than the one on the right, then the blocks are still getting closer, and the spring is still compressing. If the block on the right is moving faster than the one on the left, then the blocks are getting farther apart and the spring is expanding. The sweet spot in the middle is that transition between the block on the left moving faster and the block on the right moving faster, in other words, the moment when the blocks are moving the same speed. At this moment they are at the closest approach/maximum compression.
Thanks for the great video! It helps me understand it more. For the same type of problem in my textbook, it states that the two carts would have the same speed upon the maximum point of compression of the spring - could you please explain how is that so? Many thanks.
when the impact is about to occur, the left car must be moving faster than the right car, in order to be approaching the right car. After the impact, the left car must be moving slower than the right car, so that their separation distance can increase. The point where the maximum compression occurs is the transition point from the cars getting closer together and getting farther apart, so that's when the two speeds are equal.
Great Video, I know it's from 3 yars ago but I just wanted to say that in my opinion it would've been better if you kept going with literal analysis, wih v0 m and M and then calculate using numbers
Probably better, yeah. In my "physics for life science" courses, the students can usually avoid finding the full symbolic solution first, and in my "physics for engineers" course, the students are expected to find the symbolic solution first (and often they have to solve problems that are purely symbolic anyway). I've started to tend toward always showing a symbolic solution in my videos, because that's usually the most useful to the most viewers. z
What would make the spring squish at the first place ? Should not the moment the 2kg mass pushes the spring , the spring should at least exert some force on the 1.5 kg block which will increase its velocity? At least some velocity of block of 2kg should increase isnt it?
Yes, but it's a gradual process: compressing a spring by a tiny amount means it exerts tiny forces. The 2kg keeps getting closer to the 1.5kg even though it is slowed a little bit and the 1.5kg speeds up a little bit. This continues until the special moment when the two velocities become equal, after which the 1.5kg keeps speeding up, the 2kg keeps slowing down, and the distance between them begins to grow. z
Question about the video or requests? I will respond within 24 hours. -- Zak
why cant we plug in the initial velocity for the kinetic energy and equate that to the spring energy? shouldnt they be the same since energy is conserved?
because in the final state (the moment of max compression) the masses are still moving, so some of the energy will be in the translational kinetic energy of the masses; i.e., not all the initial energy is in the compression of the spring. z
Love from India, you are doing great work, keep it up
Thank you! -- Zak
love from india. man you didi a wordorfull job here.
Thank you very much!
I've noticed a lot of traffic coming from India lately -- I wonder if it would be helpful to close caption my videos for Indian audiences. If I did that, what do you think the most important languages would be? It's also possible the auto-translating in UA-cam isn't good enough to bother with. Interested to hear what you think. -- Zak
@@ZaksLab mostly people know hindi but English is actually fine because sometimes autotranslate might not deliver the actual meaning
@@ZaksLab Indians watch these videos for competitive exam purposes so...
Hey that's some good explanation my teachers perhaps skipped some main steps causing confusion...Great learning thanks for it!!
Thanks! -- Zak
Why would the blocks move at the same speed at max compression???
If the block on the left is moving faster than the one on the right, then the blocks are still getting closer, and the spring is still compressing. If the block on the right is moving faster than the one on the left, then the blocks are getting farther apart and the spring is expanding. The sweet spot in the middle is that transition between the block on the left moving faster and the block on the right moving faster, in other words, the moment when the blocks are moving the same speed. At this moment they are at the closest approach/maximum compression.
@@ZaksLab actually I got it by watching the solution 2-3 times, thank you btw! You're doing a great job!!
@@PrabhatSingh-mn2fl thanks!
Keep doing the good work
Thank you!
Thanks for the great video! It helps me understand it more.
For the same type of problem in my textbook, it states that the two carts would have the same speed upon the maximum point of compression of the spring - could you please explain how is that so? Many thanks.
when the impact is about to occur, the left car must be moving faster than the right car, in order to be approaching the right car. After the impact, the left car must be moving slower than the right car, so that their separation distance can increase. The point where the maximum compression occurs is the transition point from the cars getting closer together and getting farther apart, so that's when the two speeds are equal.
@@ZaksLabThank you for simplifying things, so kind of you! Really makes sense now!
Great Video, I know it's from 3 yars ago but I just wanted to say that in my opinion it would've been better if you kept going with literal analysis, wih v0 m and M and then calculate using numbers
Probably better, yeah. In my "physics for life science" courses, the students can usually avoid finding the full symbolic solution first, and in my "physics for engineers" course, the students are expected to find the symbolic solution first (and often they have to solve problems that are purely symbolic anyway). I've started to tend toward always showing a symbolic solution in my videos, because that's usually the most useful to the most viewers. z
What would make the spring squish at the first place ? Should not the moment the 2kg mass pushes the spring , the spring should at least exert some force on the 1.5 kg block which will increase its velocity? At least some velocity of block of 2kg should increase isnt it?
Yes, but it's a gradual process: compressing a spring by a tiny amount means it exerts tiny forces. The 2kg keeps getting closer to the 1.5kg even though it is slowed a little bit and the 1.5kg speeds up a little bit. This continues until the special moment when the two velocities become equal, after which the 1.5kg keeps speeding up, the 2kg keeps slowing down, and the distance between them begins to grow. z
@@ZaksLab will the 2kg one even retard after some time due to backward spring force on it
Thank u
Thanks much. subbed
Write bigger please cannot see using a phone
Thanks for the feedback! -- Zak
Good, but handwriting can be improved.
Haha, thanks? This digital pen still drives me nuts after 1000 videos, but I'm probably better now than I was then. z