Olympic Question Time: WB/OB; man on a motorbike; Ainslie's dinghy

Q. Some of the times in the heptathlon were marked 'WB' and 'OB' instead of 'WR' and 'OR'. What's the difference? Mrs G Winkworth

A. World records are rare in the heptathlon. The athletes are all-rounders, but not necessarily the world's finest in each discipline. So the "world best" score or time means the best in that event during a heptathlon. Ditto "Olympics best". It is the same in the decathlon.

Q. Who's the chap on the strange motorbike in the cycling? A Fiddes

A. He's Peter Deary, a 65-year-old coach usually based at the Manchester Velodrome. He rides the Olympics derny, an electric bike that paces the keirin race. He's there to limit the pace and bring a bit of order to what used to be a chaotic race. It crosses the start line at 30kph and slowly builds to 50kph (both speeds 5kph slower for the women), helping the riders peak for the sprint to the finish after he pulls off the track with two and a half laps to go.

Q. Is Ben Ainslie sailing basically the same kind of dinghy you can hire on your holidays? Joel Caduff

A. That's more likely to be a Laser dinghy – that's also an Olympic class, and is among the most popular dinghies in the world. The Finn is a slightly bigger beast, with a bigger sail area, but it's still sailed by only one man. They have to be strong to control the sail, and heavy enough to balance the boat.

Please send your questions to olympicquestions@independent.co.uk, or tweet using the hashtag #indyolympics, live from the stadium – or your sofa. Thanks for a huge response so far.