Answer:
The maximum speed at which the car can safety travel around the track is 18.6m/s.
Explanation:
Since the car is in circular motion, there has to be a centripetal force
. In this case, the only force that applies for that is the static frictional force
between the tires and the track. Then, we can write that:

And since
and
, we have:

Now, if we write the vertical equation of motion of the car (in which there are only the weight and the normal force), we obtain:

Substituting this expression for
and solving for
, we get:

Finally, plugging in the given values for the coefficient of friction and the radius of the track, we have:

It means that in its maximum value, the speed of the car is equal to 18.6m/s.
Hello,
Here is your answer:
The proper answer for this question is option B "When released,a book falls to the ground". That's because of gravity the book will hit the ground!
Your answer is B.
If you need anymore help feel free to ask me!
Hope this helps.
I know this question is from 2017 but I am doing this for anyone else that is looking for a answer. The answer should be C.) Allowed psychology to be considered a science.