Question

A copper bar is 80cm long at 15°C
what is the increase in length when
heated to .35°C. Given , the coefficient
of linear expansion of copper is 1.7 × 10 ‐5°C-1​

Answer 1

Answer:

Answer on Question 80073, Physics, OtherQuestion:(a) A copper bar is 80푐푚long at 15°C. What is the increase in length when it is heated to 35°C? The linear expansion coefficient for copper is 1.7∙10−5°C−1.(b) A cylinder of diameter 1.00푐푚at 30°Cis to be slid into a hole in a steel plate. The hole has a diameter of 0.99970푐푚at 30°C. To what temperature must the plate be heated? The coefficient of linear expansion for steel is 1.1∙10−5°C−1..Solution:(a)By the definition of the linear thermal expansion we have:∆퐿퐿0=훼∆푇,here, ∆퐿is the increase in length of the copper bar when it is heated to 35°C, 퐿0is the initial length of the copper bar at 15°C, 훼is thelinear expansion coefficient for copperand ∆푇is the change in temperature.Then, from this equation we can find the increase in length of the copper bar when it is heated to 35°C:∆퐿=훼∆푇퐿0=1.7∙10−5°C−1∙(35°C−15°C)∙0.8푚=2.7∙10−4푚.(b)By the definition of the linear thermal expansion we have:∆퐿퐿0=퐿−퐿0퐿0=훼∆푇,here, 퐿0=0.99970푐푚is the initial length of the steel plate at 푇0=30°C, 퐿=1.00푐푚is the length of the steel plate at temperature 푇,훼is the coefficient of linear expansion for steel and∆푇is the change in temperature.Then, we get:퐿−퐿0퐿0=훼(푇−푇0),푇=퐿−퐿0훼퐿0+푇0=1.00푐푚−0.99970푐푚1.1∙10−5°C−1∙0.99970푐푚+30°C=57°C.Answer:(a) ∆퐿=2.7∙10−4푚.(b)푇=57°C