if you jump from an airpalne(why doesn't matter) and your speed of descent is 9.8m s/s. i think that means second per second what speed are you traveling.

It means that, in the absence of air resistance or other factors that would interfere with your fall, you gain another 9.8 meters/second in speed for each second you are falling. After one second: 9.8 m/s After two seconds: 19.6 m/s After three seconds: 29.4 m/s and so on.

It depends on how long you've been falling. For each second you've been falling, you gained another 9.8 meters per second. If you have been falling 30 seconds, that's 30 * 9.8 or 294 meters per second.

More complex and faster than you suspect: Time element is squared: one second then multiplier is 1, two seconds then multiplier is 4 three secs. multiplier is is 9 four secs. multiplier is 16 5 secs. is 25... 10 seconds multiplier is 100.. 30 seconds multiplier is 900... And there is a terminal velocity the differs for objects with differing shapes and denisities. the common mouse can survive a fall of any height since its terminal velocity is survivable.: Earth's gravity, denoted g, refers to the acceleration that the Earth imparts to objects on or near its surface. In SI units this acceleration is measured in m/s2 (metres per second per second, equivalently written as m·s−2 or N/kg). It has an approximate value of 9.81 m/s2, which means that, ignoring air resistance, the speed of an object falling freely near the Earth's surface increases by about 9.81 metres per second every second. This quantity is informally known as little g (contrasted with G, the gravitational constant, known as big G). There is a direct relationship between gravitational acceleration and the downwards weight force experienced by objects on Earth (see Conversion between weight and mass). However, other factors such as the rotation of the Earth also contribute to the net acceleration and are usually considered part of Earth's gravity. The precise strength of the Earth's gravity varies depending on location. The nominal "average" value at the Earth's surface, known as standard gravity is, by definition, 9.80665 m/s2 (32.1740 ft/s2). This quantity is denoted variously as gn, ge (though this sometimes means the normal equatorial value on Earth, 9.78033 m/s2), g0, gee, or simply g (which is also used for the variable local value). The symbol g should not be confused with g, the abbreviation for gram (which is not italicized).[1][2

I thought that the square was in the distance/displacement equation. d = 0.5*a*t^2 The velocity equation is v = a*t.