Recent content by JWSiow

But, I used the number of moles found in part b) to calculate the new volume, which means if I used the new volume to calculate the mass using the same method, I'd get the same mass, and the buoyancy force would stay constant...

Homework Statement A helium meteorological balloon is made of a bag of impervious fabric that does not stretch, and when fully inflated forms a spherical shell of 1m diameter enclosing the He. At launch it is filled with He (at STP) to 15% capacity. The launch takes place in the Antarctic, in...

Ok, thanks! That makes me feel much more relaxed! (cos it seemed like something that could come up in the exam) :)

But in the textbook, it said, "You also do no work on the bag of groceries if you carry it as you walk horizontally across the floor at constant velocity"... which is why I thought no work would be done from A to B, C to D and E to F. How would I work out the net work done on the box?

Anyone? :S I need to know by tomorrow! (have an exam...)

I don't know, I don't really get the question. In the textbook, it says that you carry something in your hands, you don't do any work on it since the force to carry it is perpendicular to the displacement.

Ok, thanks. :) So, for b), when calculating the centripetal acceleration, I'd use the velocity of the platform?

Homework Statement A man picks up a 10kg box, and holds it at a height of 1m above the horizontal ground as he walks to a ramp, and then carries the box up the ramp to a height of 4m, and then down the ramp as shown, finally placing it on the ground at F. Describe the work done at each...

Homework Statement A child sits 2m from the centre of a merry-go-round (a rotating wooden platform) which is rotating at 3.5revs/min in a clockwise direction (when viewed from above). She places a wooden block of mass m=0.25kg beside her on the platform. a)Draw a diagram showing all the...

I'm not sure if my answer's correct, but I'd say the max. potential energy is the same as the max. kinetic energy because of the Law of the Conservation of Energy. ALL of the potential energy should be converted to kinetic energy, hence the max. kinetic energy = max. potential energy.

Thanks anyway :) Any answer's better than none! Hopefully they don't put anything weird like that in my exam!

Ok, thanks heaps!

Yep, that's one of the things that confused me. I assumed it meant ignore friction..

Homework Statement Two light bulbs of resistance R1=10 ohms and R2 = 15ohms are connected in series with a 25V battery. Which bulb glows more brightly? Now the bulbs are connected in parallel with the battery. Which bulb now glows more brightly? Homework Equations V=IR The...

Okay, thanks!