Could someone please help me with a question on energy and work? Please see attachment :) Thank you

Question

anonymous · Answer

attachment

anonymous · Answer

I've got the vector diagram but I'm unsure how to do part b and c.

anonymous · Answer

I tried part b and got an answer of 197 J, the answers in my book say it's 200 J

anonymous · Answer

It is laborious to draw the diagram, but the direction is : Separate the Tension into horizontal and Vertical components. Then Substract the friction force from the Horizontal component, Substract the weight mg from the Vertical component

anonymous · Answer

Since the Critically important is the fact that the crate is NOT RISING - so the overall vertical force is 0

anonymous · Answer

Yes

anonymous · Answer

BTW 197 J can be more or less 200 J - because of rounding of g or rounding of trigonometric values

anonymous · Answer

Yeah I thought so... the unrounded value I got was 196.596 and so on. My book is weird with rounding.
Would you be able to explain how to do part c please?

anonymous · Answer

The crate is moving only horizontally Delta X is horizontal. So Multiply the horizontal comp. of the tension (you shld find it by now) by the distance moved. That is all.

anonymous · Answer

Thank you so much @Mikael!