Acceleration = force / mass = 20 / 2 = 10 m/s^2
1. "<span>Physical models are usually in the form of a graph" is the statement among the statements given about physical models that is not true. The correct option among all the options that are given in the question is the third option or option "c".
2. "Predicting weather patterns" is the one among the following scenarios that </span>represents the best use of a scientific model. <span>The correct option among all the options that are given in the question is the first option or option "a".</span>
Answer:
v=32.9m/s
Explanation:
The acceleration needed to mantain a circular motion of radius r and speed v is given by the equation 
This is the centripetal acceleration. The person will feel what is called a centrifugal acceleration, of the same value, because he is not in an inertial frame (thus subject to fictitious forces, product of inertia).
We want to know the speed of his head when it is subject to 12.5 times the value of the acceleration of gravity while moving on a 8.84m radius circle, so we must do:

The correct answer is A, 2x^3 - x^2 +3x +7
Explanation:
It is based upon the fact that " The light travels faster then sound." As the speed of light is faster then the speed of sound, light travels 300,000 km per second and sound travels 1192 km per hour. That is why we observe the lightening first and hear the the sound of thunder later.
You can do this experiment by yourself. Once you see the lightening start counting the seconds until you hear the sound of thunder.Then divide the seconds by 5, you will find out how many miles away the lightening strike was.