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# Physics/acceleration due to gravity

Question
Sir I have maruti 800 car
initial speed is 0 ,final speed is 39.88m/s acceleration is 100sec
now I want to acceleration due to gravity in this in % value speed is 144km/hr

Hello vinu,

If it reaches 39.88 m/s in 100 s, then using the procedure from our previous question and answer:
Average acceleration = (39.88 m/s - 0 m/s) / 100 s = 0.3988 m/s^2

To convert to a comparison to the acceleration due to gravity, divide by the value of the acceleration due to gravity, which is 9.8 m/s^2. Continuing from above,
comparison to the acceleration due to gravity = (0.3988 m/s^2) / 9.8 m/s^2 = 0.041
Or 4.1% of the acceleration due to gravity. The usual way to give an acceleration as compared to the acceleration due to gravity would be 0.041g.

As I said before, acceleration is greatest early in a car's acceleration time period. I found data online saying your car would probably reach 100 km/h in 21 seconds. I'll assume that to be true and calculate your car's average acceleration during those 21 seconds. 100 km/h is equivalent to 27.78 m/s. Using that speed then and 21 seconds in the procedure above:
Average acceleration = (27.78 m/s - 0 m/s) / 21 s = 1.323 m/s^2

To convert to a comparison to the acceleration due to gravity, divide by the value of the acceleration due to gravity, which is 9.8 m/s^2. Continuing from above,
comparison to the acceleration due to gravity = (1.323 m/s^2) / 9.8 m/s^2 = 0.135
Or 13.5% of the acceleration due to gravity. The usual way to give the acceleration as compared to the acceleration due to gravity would be 0.135g. That is the average over the first 21 seconds.

If you recorded the speed after the first 5 seconds of acceleration, and performed the above calculations, I would guess that you might get about 50% of the acceleration due to gravity.

I hope this helps,
Steve

Physics

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#### Steve Johnson

##### Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

##### Experience

I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University