An object at rest starts accelerating if it travels 30 meters to end up going 10 m/s what was it’s acceleration

First we have to calculate the time taken to travel the distance 30 m, is

.

Now from equation of motion,

Given, .

As object starts from rest, so  u = 0.

Substituting these values in above equation, we get

 .

Thus, the acceleration is

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.