pt all questions. Question B1 [10 marks] Your mobile phone contains a micro-electronic mechanical system (MEMS) gyroscop

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Pt All Questions Question B1 10 Marks Your Mobile Phone Contains A Micro Electronic Mechanical System Mems Gyroscop 1 (50.6 KiB) Viewed 10 times

pt all questions. Question B1 [10 marks] Your mobile phone contains a micro-electronic mechanical system (MEMS) gyroscope integrated circuit to sense physical rotation. The details are complicated (and irrelevant to the ql), but it can be approximated as a mass oscillating horizontally on a spring. For the design shown, the mass is 220 ng (2.2 x 10 kg) and it oscillates at 7.0 kHz. (a) What is the overall spring constant of the spring used in the design? [2 marks] To make the gyroscope work, the mass must be made to oscillate at its natural spring-mass frequency. This is achieved using electrostatic forces (attraction of opposite charges) between the mass and the body of the device. To accelerate the mass to make it oscillate, the electrostatic force must be applied in a way that reinforces the motion. This is done by measuring the position of the mass electronically and then applying the correct force based on this. (b) Using labelled diagrams and text explain how the position, velocity, and acceleration of the mass varies with time, including the phase relationship between them. [4 marks] (c) Thinking back to your mechanics study, explain how the applied force should vary with time in order to increase the amplitude of the oscillation. [hint: what variable are you trying to affect?] [2 marks] (d) If the amplitude of the oscillation is 0.20 μm (2.0 x 107 m), then calculate and explain how much mechanical and potential energy is present in the oscillator. [2 marks]