Physics 8 Work, Energy, and Power (21 of 37) Box pushed over rough surface

This six part physics lecture series will cover the concepts of Work and Energy.

Problem Text:
A box is pushed over a horizontal rough surface a distance of 70m by a force of 120N. How much work was done?

[MichelvanBiezen]

You are welcome. I am glad this is helping.

[fatimaroque]

What would be the work done by gravity in this example?

[nasradinali]

Very clear, this professor has good natural intelligence and instinct, your videos are explained at proper phase to learn, I learned endless from your videos, great thanks

[daniyalravandeh]

Just wondering why there is no factor in W=F.d or in case of presence of Friction in our system, which apply the effect of the effective contact area (A) of our mass!!!

Is there any assumption like considering all these equation in 2 dimension while the 3rd one is usually considered as 1 in scale?

Lets put it in this way, if there is any different in W where our force is consuming to push a sphere (which has the less effective contact area with surface) in comparison with a cube while both have the same mass!!!

I don't know if friction coefficient which is usually given by question is related to our mass shape or not?

It's really made me confused at this point when I noticed that you DO NOT consider the friction effect in calculating W on that incline plane while our F is supposed to defy the g.m.sin(theta) to push it up.

[sethmamintod]

Your lectures helped me a lot, thanks Sir!

[fizixx]

Even the simple problem are fascinating and fun. Have you ever tried to do the toilet paper problem? Where the question is: Is it easier to pull the paper from on top or from on the bottom? I started doing this once, but I never finished it. I took the roll to be a pulley instead of a roll rotating about its axis. I'm gonna have to try that again.

[shunar]

Sir plz make with Sequence wise.... all r mixed... Not able to find videos plz plz.

[lunardust]

I have a question about work being equal to the change in energy..if you are pushing straight on the box and its frictionless then how is there ever a change in energy? since it does not go up hill. is it gained kinetic energy now instead of potential energy?

[albertopoli]

Is this video without sound? Or better it is

[mscook]

So helpful😄 thankyou sir still helping us till this day 👌👏

[impeccablebybirth]

Just a quick question. During the second example when you had to use the component of the force (Fx) I understand that you need to use cos30 to get the value of the force in the x direction but don't you also need to use the angle again? So wouldn't it have to be (Fcos30)(d)(cos30)= W? I thought that the first cos30 only applied to the force and you still need to put the value of the angle between them

Thanks for your lectures on YouTube I like it

[khairudinrasikh]

thanks from your effective lecture on u tube.