Work, Energy and Power grade 12: practice

Grade 12 work energy power practice question

[leratoshasha]

Using the energy principles only, calculate the magnitude of force of air friction That is exerted on body

[Vandell-ezdu]

Kevin did the long way at 5.4 u could've just calc frictional force bcoz u have Tension and Fg already and once u have friction just calc the work done as easy as that

[kurhulasharniqua]

Kevin but on 5.4 the right handside doesn't give zero(0)

[arinaomulafhi]

Can you please elucidate why is the initial velocity also 4m.s¹?

[kylie]

Very helpful video! For 5.4, could you have used Fnet=ma or do you have to use the work energy theorem? You do get the same answer.

[chadoliver]

(Question 5.4) I see that you rather calculate each force using the F×displacement×cos© instead of combining them all like in previous videos.

So my question is can you combine all the forces in the formula?

[LizoSikhothe]

5.4 why you dnt use (Wf x 20 x cos 180) on Wf as you did on Fg and Ft, bcz friction is bein calculated as a force while others are work done

[rainylizardseyes]

Sorry sir for the last question why when the block moves up the slope it's still cos180

[vincentrepinz]

Kevin?? The initial velocity was zero because it says “a rescue helicopter is stationary (hovers) above a soldier.”😞

[tshwarelolebea]

when i do 5.4 i got different answers
and i did it many times but still get the same answer but not like yours
🤔🤔🤔

[MuziMhlanga-ckwq]

But on the right side it's doesn't give you 0, please stop teaching us your own things from your head!