net force (1 Viewer)

[jessi90]

what does net force mean? how does an object in stable orbit around the earth have no net force acting on it?

 

[lolokay]

net force is the unbalanced for acting on the object that causes it to accelerate - the sum of the vector forces. An object in orbit does have a net force since it is constantly accelerating

 

[dolbinau]

*BUMP*. Could you describe an orbiting object having a net force at any one instance?

 

[wogblogger]

ok.. Orbiting object in a stable orbit at anyone instant

The Centripetal force, acts towards the center (i.e, perpendicular to its position in its circular orbit). Is of magnitude mv^2/r

note: its velocity does not increase (only changes direction). Reason being that there is no force acting in its path of motion at any instant ( i.e. the tangent at the point of its position)

i think ive stuffed up somthing in that 'note', but im tired so live with it!

 

[dolbinau]

Ok. So. Does this mean that satellites in orbit do in fact have a net force? :S

 

[Jase]

Yes. All orbiting objects have a net force. This force is provided by gravity. There is no other force opposing gravity hence the object will accelerate according to newton's law F = ma. This acceleration is directed to the centre of a circle. The reason it doesn't CRASH into the centre is because it already has inertia provided by some event (e.g. satellites need rocket thrusters to reach orbital velocity).

If they didn't have a net force, they would not orbit and would fly away due to their inertia.

 

[twilight1412]

think of it this way
if it isnt stationary
and it isnt moving in a straight line
chances are theres a net force acting on it