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Danh Thanh Nguyen
Danh Thanh Nguyen
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I don't have a physics background. (I'm a Computer Science student)

I have a waist-worn accelerometer provided by the school which is quite reliable. I've captured data of sitting still to standing still transitions from a person. Here is the result synchronised from many tests, the orange curve depicts data from the vertical axis. enter image description here

Could anybody please explain to me the pattern of acceleration data? Why does the accelerationacceleration's magnitude always increase first before decreasing? (The sign of value depends on the device's configuration so you don't need to worry about it) Should it not be the other way around?

As far as I know about physics, Newton's 2nd Law states $F = m . a$ so I would think that when the person stands up, a force in the upwards direction is created which is opposite the the Earth gravitational force which heads down so the resulting force must be lower than the original force (which only includes the Earth gravitational force) leading to a reduction in the acceleration?

Also if possible could you let me know what possibly causes the sudden drop in acceleration right after that?

Many thanks.

I don't have a physics background. (I'm a Computer Science student)

I have a waist-worn accelerometer provided by the school which is quite reliable. I've captured data of sitting still to standing still transitions from a person. Here is the result synchronised from many tests, the orange curve depicts data from the vertical axis. enter image description here

Could anybody please explain to me the pattern of acceleration data? Why does the acceleration always increase first before decreasing? (The sign of value depends on the device's configuration so you don't need to worry about it) Should it not be the other way around?

As far as I know about physics, Newton's 2nd Law states $F = m . a$ so I would think that when the person stands up, a force in the upwards direction is created which is opposite the the Earth gravitational force which heads down so the resulting force must be lower than the original force (which only includes the Earth gravitational force) leading to a reduction in the acceleration?

Also if possible could you let me know what possibly causes the sudden drop in acceleration right after that?

Many thanks.

I don't have a physics background. (I'm a Computer Science student)

I have a waist-worn accelerometer provided by the school which is quite reliable. I've captured data of sitting still to standing still transitions from a person. Here is the result synchronised from many tests, the orange curve depicts data from the vertical axis. enter image description here

Could anybody please explain to me the pattern of acceleration data? Why does the acceleration's magnitude always increase first before decreasing? (The sign of value depends on the device's configuration so you don't need to worry about it) Should it not be the other way around?

As far as I know about physics, Newton's 2nd Law states $F = m . a$ so I would think that when the person stands up, a force in the upwards direction is created which is opposite the the Earth gravitational force which heads down so the resulting force must be lower than the original force (which only includes the Earth gravitational force) leading to a reduction in the acceleration?

Also if possible could you let me know what possibly causes the sudden drop in acceleration right after that?

Many thanks.

Source Link
Danh Thanh Nguyen
Danh Thanh Nguyen
  • 3
  • 3

Sitting to Standing Posture Transition Accelerometer Triaxial Data Explanation

I don't have a physics background. (I'm a Computer Science student)

I have a waist-worn accelerometer provided by the school which is quite reliable. I've captured data of sitting still to standing still transitions from a person. Here is the result synchronised from many tests, the orange curve depicts data from the vertical axis. enter image description here

Could anybody please explain to me the pattern of acceleration data? Why does the acceleration always increase first before decreasing? (The sign of value depends on the device's configuration so you don't need to worry about it) Should it not be the other way around?

As far as I know about physics, Newton's 2nd Law states $F = m . a$ so I would think that when the person stands up, a force in the upwards direction is created which is opposite the the Earth gravitational force which heads down so the resulting force must be lower than the original force (which only includes the Earth gravitational force) leading to a reduction in the acceleration?

Also if possible could you let me know what possibly causes the sudden drop in acceleration right after that?

Many thanks.