- #1
2013
- 92
- 0
Homework Statement
Airbag Sensor
To trigger the airbag, accelerometers are used.
A simple sensor is composed of three parallel plates of the surface A, which are connected to a condenser system.
The mass m of the middle plate can move between the two fixed outer
Moving plates. She is stopped by two identical k, isolated springs of spring constants. The springs are not stressed when the plate is in the center.
To what maximum distance x, the middle plate
is deflected, when the vehicle is braked suddenly from movement at a constant acceleration a.
Determine how large the additional capacitance C must be when the airbag to trigger a voltage Uc = 0.15 V and this needs to happen at a speed of 10 ms ^ -2.
To use the values d = 1.0 cm, A = 250 cm2, m = 50 g, k = 5.0 × 102 N m ^ -1 and U = 12 V.
2. The attempt at a solution
x(t)=x0e−δt cos(ωt+φ)
x(t)= F(t)/D
C2 -C1 ≈∆d/d
Is it right what I have done?
What should I do now? How can I calculate the additional capacitance C ?