Abicyclist in the tour de france crests a mountain pass as he moves at 15km/h. at the bottom 4km/h farther, his speed is 75km/h. what is his average acceleration(m/s^2) while riding down the mountain? ,

For an uniformly accelerated motion, the following relationship can be used:

where a is the acceleration, S the distance covered, vf the final speed and vi the initial speed.

Before using the formula, we need to convert everything into SI units.
The distance covered is:

To convert the speed from km/h to m/s, let's keep in mind that


so

is the conversion factor.
So the speeds are:



and so, now we can re-arrange the formula to find a, the average acceleration:

Domain eukarya; kingdom plantae should be the answer.

45 is the correct answer