Thermperature Questions to be answered.?
1. Steel rails are in sections 20 m long. How much gap must be allowed between sections if the expected temperature change is 40°C?.
2. A certain amount of gas occupies a volume of 0.4m3 at a temperature of 300K. If the pressure is kept constant. Find the volume of the gas if it is heated to 380K?
3.A copper wire is 20m long at 0°C. How long it will be at 10°C?
1. Steel rails are in sections 20 m long. How much gap must be allowed between sections if the expected temperature change is 40°C?.
2. A certain amount of gas occupies a volume of 0.4m3 at a temperature of 300K. If the pressure is kept constant. Find the volume of the gas if it is heated to 380K?
3.A copper wire is 20m long at 0°C. How long it will be at 10°C?
-
1. look up the coefficient of expansion for steel
calculate the change in length, delta L, from
delta L = L0 alpha delta T
where L0= the original length, 20m, delta T = the change in temp, 40 deg C, and alpha is the coefficient of linear expansion
the distance you want will be twice delta L, since there are two rails that are expanding in length
2. the perfect gas law tells you that
PV = n R T
if P is constant, we see that the volume will vary linearly with the temperature, therefore if the temp increases by a factor of 380/300 = 1.27, the volume will also increase by this factor, so the new volume is 1.27 x 0.4m^3
3. use the same equation as in the first problem, look up the coefficient for expansion of copper, remember that the wire will contract; the new length will be L0 - delta L
calculate the change in length, delta L, from
delta L = L0 alpha delta T
where L0= the original length, 20m, delta T = the change in temp, 40 deg C, and alpha is the coefficient of linear expansion
the distance you want will be twice delta L, since there are two rails that are expanding in length
2. the perfect gas law tells you that
PV = n R T
if P is constant, we see that the volume will vary linearly with the temperature, therefore if the temp increases by a factor of 380/300 = 1.27, the volume will also increase by this factor, so the new volume is 1.27 x 0.4m^3
3. use the same equation as in the first problem, look up the coefficient for expansion of copper, remember that the wire will contract; the new length will be L0 - delta L