As a 1850 kg car is traveling down a road, it experiences a force of friction of 121 N and a force of air resistance if 186N. If the engine is not applying any force, what is the acceleration of the car

  -0.166 m/s²

Explanation:

F = Ma

a = F/M = (121 N +186 N)/(1850 kg) = 0.166 m/s²

The acceleration of 0.166 m/s² is in the direction opposite to the direction of travel, so might be considered to be negative.

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.