Recent content by Chris Danger

that is not the only mistake. also, i only brought in the cliff analogy to illustrate an example of how negative displacement could occur in this problem. as an answer of "65m [down]" was given, it is clearr that the rock does not fall to the ground. it is okay too say -65m as long as you...

this may suggest having to use a_{n} = \frac{v^2}{r} to get acceleration, but you would need the velocity and the mass (to get the force from F = ma)

after the rock is thrown the only force acting on it is gravity, and so the acceleration of the rock is constant. you should have some nice equations for constant acceleration that can thus be applied. for part a) you can use s - s_{0} = v_{0}t + \frac{1}{2}at^2, but be careful that your...

what is the magnitude of a + b? you need a vector of maginutude 20, in the same direction of a + b. the scale of your magnitudes should be the same as the scale of your components. (check it for yourself - can you see it's just similar triangles?) look out for this nice 3,4,5 triangle; they...

yeah, i was lying in bed thinking about this one last night. glass is pretty (thermally) non-conductive come to think of it. Also it is quite strong when not supplied in thin sheets (or after tempering), and 300 C is not that hot, really. perhaps it is glass! :blushing:

yeah, the way i saw it, glass is quite thermally conductive. also it is certainly not strong, and it softens readily with the application of heat (although i wasn't sure if 300 C is anywhere close to the TG) also diamond is way too expwnsive for any application that does not require extreme...

hi all, an intersting question in our exam today. we were asked to identify a material given these requiremets "that could have been extracted from product design specifications" "thermally non-conducting, strong at temperatures in excess of 600K, and optically transparent." any ideas?

I found it to be a great introduction to relativity for me (first part of the book). Difficult concepts are explained in ways that are very easy to understand. I have read many books on quantum physics, and found the approach of this book not to be the best (check out "The Mystery of the Quantum...

What about using impulse, if you have the time and initial and final velocities? Then F(ave)*t = m*(Vf-Vi).

Isn't it that the electrons of the book's molecules are close enough to the electrons of the table's molecules to provide sufficient repulsive force to keep the book afloat? (They're not really touching!)

Hi Alisa, You are taking the time to be only those cars that have passed the pedestrian in one direction, but have not counted the cars that are still on the tracks inbetween stations (that have left, but not yet caught up to the person). You can find this number of cars using information...

Hi, I think the reason why you feel the force greatest when heading towards the top of the loop is because that's when your speed is greatest. As you change direction you are accelerating (regardless of whether or not your speed is changing), and in this case, the force needed to accelerate...