Answer:
A baseline score of 99% needs to be set.
Step-by-step explanation:
Since this is an example of a classification problem (the classes being whether somebody has been infected with a new virus or not), the ideal score to achieve in such a case is 100%. Hence, a baseline score of 99% should be set in order to get to 100% by outperforming it.

First, let's deal with the fraction in the denominator of the exponent. Multiply the top and bottom of the exponent by 6.

Now that the fraction in the denominator is taken care of, we can reduce the denominator.
. Some professors might accept this as simplest form, but others might ask you to get rid of the negative.

The answer is: 
The explanation is shown below:
1. Cynthia rounds the number, which is identified as
, to one decimal place and the result is 6.3.
2. Based on this, we know that
could have been between 6.25 and 6.35. Therefore, the error interval for
is given by:

Where
indicates that the value 6.25 is included and
indicates that the value 6.35 is not included (Because if
had been exactly 6.35, Cynthia would round up to 6.4).
Answer: Ball's kinetic energy became potential energy
Step-by-step explanation:
There are no options attached but this should be along the lines of what happened.
Kinetic energy refers to energy that an object has as a result of it moving whilst potential energy is the opposite and is energy that an object stores within itself due to several factors whilst it is not in motion.
The ball was initially in motion which means that it had kinetic energy but as the ball was slowing down, this energy was gradually converted to potential energy until the balls came to a standstill.