Physics 8 Work, Energy, and Power (27 of 37)

In this five part lecture series I will continue where we left off on our original Work and Energy lecture series and introduce you to the concept of power.

Problem Text:
A box of 20kg is pushed against a horizontal spring of spring constant k=1200N/m compressing the spring by 30cm. After being released, the block slides 5.0m over a horizontal surface (k=0.2) before reaching a frictionless incline of 30 degrees. how far up the incline with the block slide?

[MichelvanBiezen]

Lismary,
I took a note of your request.
It takes a little while before we can get a video through our filming cycle and production cycle.

[rowanfelicite]

Thank you for sharing solutions for these types of questions. We usually encounter these questions during exams and it is not fun lol.

[marcochimio]

What a great way to take a problem that had a small error in it and turn it into something special. Very cool.

[zDoubleE]

i wish there was a higher education reformation where students were capable of taking courses from tutorial services such as yourself and still count as a credit towards our degree. My issue with "weed out" classes is you pay a lot of money for a service that isn't provided because of its deliberate design to discourage students. If a business tried doing this in the private sector, it would quickly go out of business.

thank you for your work and your many examples which, not only provides set-up examples, but provides them in such that it reinforces all the concepts we are learning in school.

[antoni]

I appreciate your support and time, thanks

[franh]

Thanks to this video I aced my physics quiz today. Thank you so much!

[christopherwilkins]

Very Nice. I forget we can skip all the inbetweens for these multistage problems. The way you showed how you can backtrack helped clear up a few of my other misconceptions as well. I keep wanting to treat each stage as its own PE-final or KE-final and it gets tedious, not to mention unnecessary >.>

[ahmedal-ebrashy]

I was pulling my hair for half an hour on why d was negative and then when I watched, I did love the video as there is indepth analysis and a new way to think of the problem. Thank you.

[Mortgageman]

This video makes sense except for one little detail, since there is an instantaneous moment which the surface switches from flat to sloped, won’t that moment act as a collision? We would lose even more heat that way

[fizixx]

Gotta say I might have been stumped by the negative result, but it's what gives this problem an extra element of learning capacity, in my opinion.

[unbelievable]

Instead of potentional energy with height i used mgsin theta * distance and got the same negative result. Seems like it would work too

[emmagracebeauty]

Also I am doing a rube Goldberg rn and in my energy box project we are supposed to show how our calculations show transformation of energy. In mine I have marbles going down ramp and hitting another marble. We must use energy not momentum and impulse and I'm confused. For future students can u do a vid on collisions calculations using ENERGY not impulse and momentum and elastic stuff?? Ty

[RiaziMohandesi]

It would be better to change the compression of spring to 1 meter so the block have enough energy to make it up incline.

[HashemAljifri]

What about the sign convention? The friction causes negative work??

[reanaptel]

Hello! I have a question. For some reason I was expecting kinetic energy to be an intergral element in this problem. I say this because from the moment the block departs from the force of the spring to the top of the ramp, wouldn't kinetic energy be part of the equation, particularly, Energy Final?

[rajaryan]

In India high school kids are solving this problem for fun ..

[sthelilesihle]

Sir, why didn`t we assume that energy loss is 0 as we are considering the mechanical energy after(up the incline)- just so we consider the fact that there is no friction up the incline

[majedsad]

This is an amazing detailed problem! Thanks!

[sccm]

Very tricky problem but I'm glad I learned how to work problems like this. I'm kind of tired of easy problems

[Nothing_serious]

I'm confused. Shouldn't the heat lost become positive because the work done by friction is negative? Since friction acts opposite of the box's displacement, shouldn't work by friction equal to friction force times distance times cos(180) which would make it negative?