Q1.
The magnitude of average acceleration of cars is generally specified as the time taken by the car to go from 0 km h⁻¹ to 100 km h⁻¹. Look it up on the internet and find this time for various cars, and record those in Table 4.2.
Table 4.2, page 55 — the magnitude of average acceleration in a time interval (printed blank in the book, for you to fill in).
| Car type | Time interval during which the speed goes from 0 to 100 km h⁻¹ (s) | Magnitude of average acceleration (m s⁻²) |
|---|---|---|
Answer
First convert the change in speed into SI units, because the acceleration must come out in m s⁻².
change in speed = 100 km h⁻¹ − 0 km h⁻¹ = 100 km h⁻¹
100 km h⁻¹ = 100 × 1000 m / 3600 s = 27.8 m s⁻¹
100 km h⁻¹ = 100 × 1000 m / 3600 s = 27.8 m s⁻¹
Now look up the "0–100 km h⁻¹" time quoted by the manufacturer or a road test for each car and fill the middle column. Typical published values look like this — treat them as a model; the whole point of the activity is that you find and record real figures yourself.
| Car type | Time interval during which the speed goes from 0 to 100 km h⁻¹ (s) | Magnitude of average acceleration (m s⁻²) |
|---|---|---|
| Small hatchback | 12.0 | 2.3 |
| Mid-size sedan | 10.0 | 2.8 |
| SUV (turbo-petrol) | 8.5 | 3.3 |
| Electric hatchback | 7.0 | 4.0 |
| Sports car | 3.5 | 7.9 |
Tip: keep the third column to two significant figures. The published 0–100 time is itself only quoted to about a tenth of a second, so quoting the acceleration to three decimals would be false precision.