Q. Is the gold medal really made of gold? Steve Hill
A. It's been a century since gold medals really lived up to the billing. This year's weigh 375-400g, but only contains 6g of gold, which is worth just under £200, using a gold price of around £33 per gram. If it were solid, you'd be looking at over £13,000 per medal. The rest of the "gold" medal is made up of silver (92.5 per cent) and copper (6.16 per cent).
Q. In this week's tennis, something odd happened with the scoring after Murray and Robson reached one set all – they got a score of 10-7. Please explain. Janet Morgan
A. It's the usual scoring system used for doubles on the pro tour. It's called a "champions' tie-break". If a doubles match goes to one set all, rather than play a third set, the match goes to a champions' tie-break, which is like a normal tie-break but played to 10 points rather than seven.
Q. In which sports are BBC cameras covering the action, and which countries are covering the rest? Laura Murphy
A. In fact, the Olympic Broadcasting Service controls all coverage. It also provides the timings you see on screen. This was an issue in the cycling road race, when there was little or no information on how far Team GB were behind the breakaway group. It also crops up when the race for gold is settled but there's a Brit in a scrap for bronze – the BBC can't just switch to pictures of that.
Q. Many women competitors are sporting some very nifty nail polish jobs, often with their national flag. Are there team manicurists? Ros Liddiard
A. No, but there is a big Proctor & Gamble-sponsored salon in the Olympic Village, where athletes go for manicures. Flags are a speciality.
Please send your questions by email to firstname.lastname@example.org, or tweet using the hashtag #indyolympics, live from the stadium – or your sofa. Thanks for a huge response so far (and please remember we can't reply to everyone). Keep them coming!