Recent content by spiruel

Homework Statement A vessel containing 500 g of water, at a starting temperature of 15.0 ◦C, is placed in a freezer at −10.0 ◦C, and left to freeze. (i) If the heat capacity of the vessel is negligible, show that the total entropy change for the system of the water and the inside of the...

Thank you for the help so far. How would I go about using the above expressions to obtain a result for the torso mass and arm masses together?

Thank you for the reply. Would the expressions below be along the right lines? I_{in} = \frac{1}{2}*M_{torso}*r_{torso}^2 + m_{arms}*(r_{torso}+r_{folded arms})^2 I_{out} = \frac{1}{2}*M_{torso}*r_{torso}^2 + m_{arms}*(r_{torso}+r_{outstretched arms})^2

Homework Statement If you have data such as time of rotation when arms are extended and the lengths of their folded and extended arms measured from the centre of the skater. I know I1ω1=I2ω2 and can work out ω from the radius and time of rotation. Where can I go from here to estimate the mass...

I'm trying to prove that $$\dfrac{l}{c+u}+\dfrac{l}{c-u}=\dfrac{2l}{\sqrt{c^2-u^2}}$$My workings so far: $$\dfrac{l}{c+u}+\dfrac{l}{c-u},$$ put over common denominator, $$\dfrac{l(c-u)}{(c-u)(c+u)}+\dfrac{l(c+u)}{(c-u)(c+u)},$$ $$\dfrac{l(c-u)+l(c+u)}{(c-u)(c+u)},$$ expand out...

Homework Statement Put of curiosity I have tried to derive a formula for the time period of a pendulum that oscillates under gravity. Below you can find my workings, which I have checked on wikipedia and the workings are practically identical. However I got stuck at one point, and this is...

Think I got it (in terms of time, not velocity): 2pi*sqrt((radius of planet+orbital altitude)^(3)/(GM))-rotationalperiodofplanet

I may be being stupid here... But I'm trying to derive such an equation to no avail. Maybe such a formula requires more than one variable - but I would like to easily display this graphically. To start out the derivation I stated that the Surface Velocity = (2pi/T)-(v/r) where v/r=angular...