Moon landing

[mr.bungle]

What does m/s2 mean when talking about gravity?

[burnhal]

It is a measurement of acceleration and stands for metres per second per second. On the earth, the value due to gravity is 9.81 ms2

[burnhal]

oh- and on the moon it is much less- due to very muc reduced gravity- arounf 0.003 ms2

[mr.bungle]

O.K I understand metres per second and i guess that means how far something would fall per second? But why metres per second per second?

[burnhal]

acceleration- something falling gains speed- it doesnt fall at a constant speed.

[mr.bungle]

O.k but have i got this right? Something will fall in the earths atmoshere at 9.81 m/s and accelate to 9.81 metres per second faster until it is falling at consant velocity?

[mr.bungle]

burnhal why do you know about this stuff?

[mr.bungle]

Sorry what i mean is are you a proffesor or something?

[mr.bungle]

Meant proffesser

[sddsddean]

Theoretically the object will continue to accelerate all the time at 9.81 m/s/s, but because of wind resistance and other friction sources, it will get to a 'terminal velocity' where it cannot accelerate anymore. Since we know that 'terminal velocity for a person is about 130mph, you can work out the time it takes to accelerate to this speed.
u (initial velocity)=0
v (final velocity) = about 130mph = 58m/s
a (acceleration ) =9.81 m/s/s
t (time) is what we want

v-u =at or t=(v-u)/a = 58/9.81 = 5.9 seconds

This is the applied maths answer, but not the true answer as you should take into account friction from wind etc.

In answer to your other query, I don't expect burnhal is a professor, as this is basic GCSE maths & physics.

[THECORBYLOON]

The "per second squared " means the speed increases by that amount each second. The speed of gravity is about 32 feet per second squared so after one second it's 32' per second, after two seconds it's 64' per second and after three, it's 96' per second.

[mibn2cweus]

burnhal, The Moon's gravitational acceleration is approximately 1.6m/s� (on the lunar surface).

An interesting property of gravitational acceleration is that it diminishes with the square of the distance; (at twice the distance it falls to one-fourth the rate). The moon being about 60 times the Earth's radius in distance from the Earth, the Earth's gravitational acceleration at that distance is about 9.81/60� = 9.81/3600 = 0.0027m/s�

The mutual gravitational attraction between the Earth and Moon causes the Moon to �fall� towards the Earth at a rate of 1.37millimetres per second; this keeps the Moon from flying out into space as it orbits the Earth!

The maximum gravitational acceleration from the Moon felt on Earth is about 0.00004m/s� (typically about 0.000033m/s�)

Also keep in mind that while 9.81m/s is the velocity gained by an object in free fall near the Earth�s surface, beginning from a state of rest, it only falls half that far (4.9 metres) in the first second because that is its average velocity over that period of time.

Isaac Newton virtually invented gravity. Thanks to him we know a lot about Free Fall and the Acceleration of Gravity

[taichiperson]

Isaac Newton discovered gravity, he did not invent it - it was there a long time beforehand!!!!!

[mibn2cweus]

Busted . . . again!!!

Isaac Newton did not discover (or invent!!!) gravity. He greatly improved our understanding of what contributed to �weight�, its relationship to mass and distance and how this relationship extended out into the universe and caused celestial bodies to orbit each other.

The term �gravity� comes from �gravitas�, the Latin word for heaviness or weight.

Einstein with his contribution of general relatively has further improved our understanding of the laws governing gravity.

Newton was doubtfully the first person to have an apple fall on his head.