Advanced Physics Help Needed [update]

last SG · 2008-03-15T15:02:55+00:00

phew thanks.. i hit a wall at those questions, i managed to do some *removed those alrdy* ps: what level of education are u at hey o.o!

WoAiMeiMei SG

i cant do this question! >_<

A steel rod is 2.894 cm in diameter at 23.00°C. A brass ring has an interior diameter of 2.887 cm at 23.00°C. At what common temperature (in Celsius) will the ring just slide onto the rod? Give your answer to four significant figures. The linear expansion coefficient of steel is 11.00 x 10^-6 /C°. The linear expansion coefficient of brass is 19.00 x 10^-6 /C°.

eagle SG

I guess for you, it is probably the algebra that killed you. We use the above equation because we consider the linear expansion of the diameter.

the ΔT is the same for both, final diameter D is also same for both
Let As = linear expansion coefficient of steel
Ab = linear expansion of coefficient of brass

and ΔLs for steel is ( D - 2.894 )
ΔLb for brass is ( D - 2.887 )

rearranging the above equation
ΔT for steel is (D - 2.894)/(2.894*As)
ΔT for brass is (D - 2.887)/(2.887*Ab)

since ΔT is the same for both, equating

(D - 2.894)/(2.894*As) = (D - 2.887)/(2.887*Ab)

Solving for D should give us the answer.

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