Why is it that when we solve an equation for throwing a ball into the air, that when the ball is going up it is regarded as negative and when it is going down it is regarded as positive.
Thank You
2007-03-13 01:09:16 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The force of gravity acts towards the centre of the Earth i.e. downwards. Gravity accelerates things TOWARDS the centre of the Earth.
The +ve direction of a force is the direction it acts in, in this case for gravity it is downwards from our perspective.
When you throw a ball upwards, gravity does work against it, therefore the ball is negatively accelerating i.e. retarding
The ball's maximum acceleration (and velocity) is when you have released it, from then on it is slowing down.
Hope this helps.
2007-03-13 01:30:47 · answer #1 · answered by Doctor Q 6 · 0⤊ 0⤋
When a ball or any other object falls towards the earth, it is taken positive coz it is in favor of force of gravity(i.e attraction of earth towards the things to its center) but when any object going up its against the force of gravity so we take it as a negative value...
2007-03-13 08:48:38 · answer #2 · answered by Rain 3 · 0⤊ 0⤋
in the gavity problems because the direction of gravitation acceleration "g" is downward, so the downward direction conventionally regarded as positive & upward regarded as negative.
2007-03-13 08:48:32 · answer #3 · answered by arman.post 3 · 0⤊ 0⤋
It is simply a convention to take "g" as a positive value. Everything follows from that.
2007-03-13 08:28:28 · answer #4 · answered by lunchtime_browser 7 · 0⤊ 0⤋