Steel rails 24.0 m long are laid end to end with gaps between them to account fo

ID: 1402379 • Letter: S

Question

Steel rails 24.0 m long are laid end to end with gaps between them to account for thermal expansion.

Part A

If the track is laid when it's 15 C, how large should the gaps be to allow temperatures up to 35 C?

Express your answer to two significant figures and include the appropriate units.

ANSWER IS NOT0.0062

Part B

If the track is laid using the gaps you found in part (a), how large will the gaps be on a -21 C winter morning?

Express your answer to two significant figures and include the appropriate units.

ANSWER IS NOT 0.174

here,

part A)

change in temprature , T = 35 - 15

T = 20 degree C

initial length , L = 24 m

linear expansion coefficient for stell is , alpha = 12 * 10^-6 K-1

delta L = alpha * L * T

delta L = 12 * 10^-6 * 20 * 24

delta L = 5.76 *10^-3 m

the gaps should be atleast 5.76 *10^-3 m

part B)

change in temprature , T = -21 - 15

T = -36 degree C

initial length , L = 24 m

linear expansion coefficient for stell is , alpha = 12 * 10^-6 K-1

delta L = alpha * L * T

delta L = 12 * 10^-6 * (36) * 24

delta L = 1.04 * 10^-2 m

the gaps length in winter is 5.76 *10^-3 + 1.04 * 10^-2

the length of gaps in winter is 0.016 m

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