in the following question(adsbygoogle = window.adsbygoogle || []).push({});

http://stommel.tamu.edu/~esandt/Teach/Summer00/CVEN305/Examples/Set3/prob3413.jpg

while G and J are parameters and the moment changes by the function M(x)=t*x

i am asked to find the angle of twist from one end to another

i know

dθ/dx=M/(GJ)

therefore

dθ=M/(GJ)dx

dθ=tx/(GJ)*dx

since t,G,J are independant of X

[tex]\int[/tex]dθ=t/(GJ)[tex]\int[/tex]xdx from 0 to L

θ=tL^2/(2GJ)

but the correct answer

θ=tL^3/(6GJ)

i can see that they have integrated twice, i can only imagine that they integrated once to find the total torque and the second time to find the angle,,,

but surely this should come from the differential equation? surely if M is a function of X and i integrate dx i souldnt need to sum up the torqe seperately??

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Angle of twist due to linear varying torque

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**