- #1
jprecinos
- 11
- 0
I am a bit confused about what accelerometers actually measure and hopefully somebody can help me resolve the following scenario:
Say we have a vehicle with mass m, fixed CG location and subject to
gravity. The vehicle is traveling at constant speed in the X
direction heading to a cliff. When it reaches the edge it loses
grip, rolls over, goes into free fall and hits the ground. With enough information we could calculate the acceleration vector of the CG of the vehicle at all times. I understand that in theory we would have zero acceleration during the straight line,-1G magnitude during free fall and depending on the impact velocity and duration of impact a very large deceleration vector when the vehicle hits the ground.
Now here is the question: We have the exact same scenario but we
decide to attach a 3 axis accelerometer at the CG of the vehicle,
oriented in the same way as the vehicle coordinate system.
As the vehicle travels to the cliff at constant speed what would the
accelerometer read? Would it read 1G or -1G?
What about during the free fall, would we have a reading in any direction?
Finally at impact would the acceleration of scenario 1 and scenario 2
differ only by the addition of another vector in the -1G global
direction? Do accelerometers care about what is going on outside their reference frame?
thanks for the help. JP
Say we have a vehicle with mass m, fixed CG location and subject to
gravity. The vehicle is traveling at constant speed in the X
direction heading to a cliff. When it reaches the edge it loses
grip, rolls over, goes into free fall and hits the ground. With enough information we could calculate the acceleration vector of the CG of the vehicle at all times. I understand that in theory we would have zero acceleration during the straight line,-1G magnitude during free fall and depending on the impact velocity and duration of impact a very large deceleration vector when the vehicle hits the ground.
Now here is the question: We have the exact same scenario but we
decide to attach a 3 axis accelerometer at the CG of the vehicle,
oriented in the same way as the vehicle coordinate system.
As the vehicle travels to the cliff at constant speed what would the
accelerometer read? Would it read 1G or -1G?
What about during the free fall, would we have a reading in any direction?
Finally at impact would the acceleration of scenario 1 and scenario 2
differ only by the addition of another vector in the -1G global
direction? Do accelerometers care about what is going on outside their reference frame?
thanks for the help. JP