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King Hiero's Crown - Isaac Physics Question

Hi all,
I'm currently struggling with part c) of this question, could anyone advise further?
https://isaacphysics.org/questions/hieros_crown?stage=a_level
the question says any arbitrary mass of silver with the mass of gold being the same. this means we can assign a random mass for silver, so long as we assign the same mass for gold. So let’s say mass of silver = 10g. Then calculate volume of silver 10/10.49 = 0.953. Then calculate volume of gold 10/19.32 = 0.518. Silvers volume/golds volume will give u how many times greater the volume is of silver. so 0.953/0.518 = 1.84

in terms of the water thing this is referring to the volume of water that will be displaced if we place these metals in water, in which case this is proportional to the volumes themselves, so the ratio of water displaced by silver/water displaced by gold = volume of silver/volume of gold.

hope this helped:smile:
Reply 2
Original post by user123569648
the question says any arbitrary mass of silver with the mass of gold being the same. this means we can assign a random mass for silver, so long as we assign the same mass for gold. So let’s say mass of silver = 10g. Then calculate volume of silver 10/10.49 = 0.953. Then calculate volume of gold 10/19.32 = 0.518. Silvers volume/golds volume will give u how many times greater the volume is of silver. so 0.953/0.518 = 1.84

in terms of the water thing this is referring to the volume of water that will be displaced if we place these metals in water, in which case this is proportional to the volumes themselves, so the ratio of water displaced by silver/water displaced by gold = volume of silver/volume of gold.

hope this helped:smile:


Yes, thanks a lot!
Original post by yuv_c
Hi all,
I'm currently struggling with part c) of this question, could anyone advise further?
https://isaacphysics.org/questions/hieros_crown?stage=a_level


Have you read the hints?
HINT 3: Determine how the density is given in terms of fractions of silver and gold masses relative to the mass of the crown.


Let the fraction of silver be x.
xρsilver+(1x)ρgold=ρsilver + gold  x \rho_{\text{silver}} + (1-x) \rho_{\text{gold}} = \rho_{\text{silver + gold }}

You use the info from part B to compute the density of the alloy (mixture of silver and gold).

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