Recent content by Caio Graco

Is a constant vector field like F = kj conservative? Since the work of F for any closed path is null it seems that F is conservative but for a force to be conservative two conditions must be satisfied: a) The force must be a function of the position. b) The circulation of force is zero. My...

If you search on Google, you will see that nonconservative and dissipative forces are given as synonyms. Just as noted @ jbriggs444 in post # 6: "However, the quick trip to Google indicates that many sources consider" dissipative "and" non-conservative "to be synonymous." So can I say that a...

Considering the paper-block system it is easy to see that my hand pulling paper is the one who performs work on the system. But if we consider as a system only the block, who does work on the system (on the block)? According to what we discussed in the above posts is the static friction force...

By the time the elevator passes the second floor, my kinetic energy is greater than it was at the beginning. So the total work on me is positive. And I believe this shows that the normal force is not conservative because there is at least one case, like this, in which in a closed trajectory the...

It is true. If you pull the paper so that the block returns to the initial position (under any trajectory) for the same initial rest condition, the work will be zero for any trajectory, which would at first indicate that the static frictional force is conservative. However, if the initial...

OK thank you. It is easy to see that if the paper is pulled into the starting position, bringing the block to the starting position also (at rest), the total work on the block will be zero. Does this mean that the static friction force is conservative?

Consider a block on a sheet of paper. If the sheet is pulled without sliding the block, who has done work on the block (since it has undergone a kinetic energy variation)? I can not see another force doing work other than the static frictional force on the block.

Consider a body inside an elevator. When it goes up and down, I believe that normal work (positive on the rise and negative on the descent). My question is: since the total work on the closed path is zero, can we say that the normal force is conservative?

I agree. It's just a matter of formality.

Ok.

When writing this it is being said that a vector is equal to a number. A vector can only be a vector and a number can only equal a number.

The problem is that he wrote ##\vec g= - 9.8 m/s^2## The correct is ##\vec g= -9.8 \vec j m/s^2## (vector equation) or else I could write ##g=-9.8 m/s^2## (scalar equation)

Exactly

OK Alright.

For this, see post # 5 "ignored".