2. You would need to alter your aiming angle, but only slightly. This is because the further you are from the target, the more time gravity has to affect the bullet.
3. Having the wind blowing parallel to the track would help a 400m sprinter because it would push him/her along the track ever so slightly. However, if the track is curved for a 400m sprint, as usual, it would both hinder and help the sprinter; therefore cancelling both forces for and against the sprinter and as a result, does not affect the sprinter.
8. A double somersault is the same as 720 degrees and so a trampolinist would have to complete 720 degrees in 10m. This means they would have to rotate 72 degrees in 1m and therefore must rotate at a speed of 72 degrees/s
10. The edge of the court is 18' longer the average professional serve is approximately 125mph so to get the tennis ball from the edge of one court to the "T" of the other side would take about 5/10's of a second and 6/10's to reach the edge, according to tennis physicist Howard Brody* so it would take a tennis ball about 1/10 of a second longer to reach the edge of the court.
* reference: http://www.tennisplayer.net/public/tour_strokes/bobby_bernstein/the_%20…