Qualification > Sciences

PHYSICS HELP!!!

<< < (2/2)

astarmathsandphysics:
3) In a tidal barrage scheme, the area of sea-water behind the barrage is 30km2, the tidal depth is 10m and the density of the sea-water is 1030 kg/m3
a) what is the energy possibly available from this scheme in one cycle of ebb and flow?
b) If one ebb and flow takes 12hrs and 40min, what avg power does this represent?
c) What practical problems are bound to occur if max energy output per cycle is to be achieved?

a)dE=ghdm=gh(30(1000)2*1030dh) since the mass of water in layer dh, dm=pgAdh

Then E=

b)1.514*10^12/(12*3600+40*60)=33.21MW

c)Controlling the rate of flow to achieve steady output. It will be hard to maintain output near the endwhen pressure of water is low.

astarmathsandphysics:

4) The steel cable on a crane has a diameter of 13mm. What force is necessary to to produce a strain of 0.1% in the wire?
What is the max acceleration with which it can lift a load of mass 1000kg if the strain in the cable is not to exceed 0.1%. The young modulus of the high-tension steel used is 2.4x1011 Pa. (Be certain to draw a free body diagram for the load)
A=pi*r^2=3.14*(6.5*10^-3)^2=1.327*10^-4m2 and strain of 0.1% means e/l=0.1/100=0.001
Y=Fl/Ae so F=YAe/l=2.4*10^(11)*(1.327*10^-4)*0.001=31820N

ma=T-mg
1000a=31818-1000*9.8=22048 so a=22048/1000=22m/s2 roughly

nid404:
Thank you ;D

Navigation

[0] Message Index

[*] Previous page