Final answer:
The technique of a swimmer reacting to the start signal in a race is aimed at improving reaction time, which is critical for competitive success. Measuring elapsed time accurately in sports often involves electronic devices to minimize human reaction time errors. Proper hand movements and body postures in swimming can minimize resistance and prevent injuries.
Step-by-step explanation:
A swimmer reacting to the horn or gun at the start of a race is demonstrating a technique to improve reaction time. This is a critical skill in competitive swimming where races can be won or lost based on how quickly a swimmer starts after the signal. In such cases, the reaction time can be the difference between first and second place.
When measuring elapsed time in sports, electronic detection methods are often used to minimize the delay that comes from human reaction times. In swimming, as soon as the start signal is given, swimmers must explode off the blocks with as little delay as possible for an optimal performance.
Regarding the hand movement and impulse experiment: When catching a ball by 'giving' with the motion, there is less impact force involved since the hands are moving with the ball, reducing the chance of dropping it. Hitting water with a flat palm creates a large splash and resistance, illustrating poor technique such as a belly flop, while entering water with fingers first and your hand shaped like a dive results in minimal splash and resistance, showing how a proper dive minimizes the impact and allows for a smooth entrance into the water. Swimmers and other athletes are advised to avoid flat-handed impacts and uncontrolled postures which can lead to injury and lessened performance.