Question

m Time Left:0:50:14 Bryanna Adams: Attempt 1 Question 11 (5 points) According to the US Mint, pennies are made of a mixture of Copper (density 8.96 g/cm3) and Zinc (density 7.14 g/cm3) What should the penny's density be if it is completely made of copper? What should the penny's density be if it is completely made of zinc? What is the range of density for a penny made of a mixture of copper and zinc? 10 of 11 ouestions saved Submit Quiz W MacBook Air 44 F4 Fr & $ 4 # 9 7 6 3 T E R CO Y 5 LL

Answer 1

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Rho_mix = rho_1 v_1 + rho v_2/v_1 + v_2, rho_1 = 8.96 g/cm^2 rho_2 = 7.14 g/cm^3 (i) completely made of copper: - rho_mix = rho_1 v + rho_2 0/v + 0, v_1 = v, v_2 = 0 = rho_1 v/v = rho_1 = 8.96 g/cm^3 (ii)completely made of zinc: - rho_mix = rho_1 v_1 + rho_2 v_2/v_1 + v_2, v_1 = 0, v_2 = v = rho_1 0 + rho_2 v/0 + v = rho_2 = 7.14 g/cm^3 (iii) if made up of zinc implies rho_mix = 7.14 g/cm^3 if made up of copper implies rho_mix = 8.96 g/cm^3 if half of the portion made up of copper and half is made of zinc implies rho_mix = (7.14 + 8.96)/2 = 8.05 g/cm^3 so we can say that density of mixture lies in between the densities of copper and zinc: - (7.14 g/cm^3) lessthanorequalto rho_max lessthanorequalto (8.96 g/cm^3)