146592 The densities of a certain material at $10^{\circ} \mathrm{C}$ and $40^{\circ} \mathrm{C}$ are $2.5 \mathrm{gm} / \mathrm{cm}^{3}$ and $2.49 \mathrm{gm} / \mathrm{cm}^{3}$, respectively. The average value of the coefficient of linear expansion of the material in this temperature range is
146592 The densities of a certain material at $10^{\circ} \mathrm{C}$ and $40^{\circ} \mathrm{C}$ are $2.5 \mathrm{gm} / \mathrm{cm}^{3}$ and $2.49 \mathrm{gm} / \mathrm{cm}^{3}$, respectively. The average value of the coefficient of linear expansion of the material in this temperature range is
146592 The densities of a certain material at $10^{\circ} \mathrm{C}$ and $40^{\circ} \mathrm{C}$ are $2.5 \mathrm{gm} / \mathrm{cm}^{3}$ and $2.49 \mathrm{gm} / \mathrm{cm}^{3}$, respectively. The average value of the coefficient of linear expansion of the material in this temperature range is
146592 The densities of a certain material at $10^{\circ} \mathrm{C}$ and $40^{\circ} \mathrm{C}$ are $2.5 \mathrm{gm} / \mathrm{cm}^{3}$ and $2.49 \mathrm{gm} / \mathrm{cm}^{3}$, respectively. The average value of the coefficient of linear expansion of the material in this temperature range is