Consider the following actions : 1. Detection of car crash/collision which results in the deployment of airbags almost instantaneously 2. Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive 3. Detection of the tilt of the smart-phone which results in the rotation of display between portrait and landscape mode In how many of the above actions is the function of accelerometer required?
- (a) Only one
- (b) Only two
- (c) All three ✓ UPSC's answer
- (d) None
Why the answer is (c)
• An accelerometer is a micro-electromechanical sensor that measures acceleration (change in velocity) along one or more axes, including the constant pull of gravity.
• Airbag systems use accelerometers to detect the sudden deceleration of a crash and fire the airbag within milliseconds (action 1).
• Laptops use an accelerometer to detect free fall — the momentary absence of gravity — and park the hard-disk heads before impact (action 2).
• Smartphones use the accelerometer's reading of gravity's direction to tell which way is 'down' and rotate the display accordingly (action 3).
• Hence all three, option (c).
Why the other options are wrong
- (a) Only one
- All three actions, not one, rely on accelerometers.
- (b) Only two
- All three use accelerometers, not two.
- (d) None
- Each action is a standard accelerometer application.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2023, held on 28 May 2023. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.