## College Physics (4th Edition)

(a) We can find the ratio of tensile strength to the density of tendon: $\frac{80.0\times 10^6~N/m^2}{1100~kg/m^3} = 72,700~m^2/s^2$ We can find the ratio of tensile strength to the density of steel: $\frac{0.50\times 10^9~N/m^2}{7700~kg/m^3} = 64,900~m^2/s^2$ Pound for pound, tendon is stronger than steel under tension. (b) We can find the ratio of tensile strength to the density of bone: $\frac{160\times 10^6~N/m^2}{1600~kg/m^3} = 100,000~m^2/s^2$ We can find the ratio of tensile strength to the density of concrete: $\frac{0.40\times 10^9~N/m^2}{2700~kg/m^3} = 148,000~m^2/s^2$ Pound for pound, concrete is stronger than bone under tension.