Because you need to know how/ learn to try new things for (new experiments) and creativity will teach you different ways on how to do it.
For 100m Race ,
displacement = distance covered .
divide the above equation by time t (assuming it takes t time to complete 100m race),
we get,
velocity = speed.
and for 400m race 1 lap is completed this means that racer's initial and final position coincide (or same) hence,
displacement = 0,
distance ≠0=400m.
=> displacement ≠distance.
=> velocity ≠ speed.
4 m/s^2
I hope this helps!
I know this isn't the answer but here's an English translation
<span>The saturated vapor pressure of pure water at 20 ° C is 18 mmHg. If at the same temperature as much as 120 grams of x-substance dissolved in 990 grams of water, the vapor pressure of the solution becomes 17.37 mmHg, calculate the relative molecular mass of the substance x?</span>