Answer: Option A; 9.8 m/s^2
Explanation:
When an object is in the air, and there is no air resistance acting on the object, the only force that will act on the object is the gravitational force (on the vertical axis).
Then, if the only force acting on the object is the gravitational force, the acceleration of the object will be equal to the gravitational acceleration.
We know that the gravitational acceleration is equal to:
g = 9.8m/s^2
Then the acceleration on the vertical axis will be equal to:
a(t) = 9.8m/s^2
The correct option is the first one:
A. 9.8 m/s^2
First of all, let's write the equation of motions on both horizontal (x) and vertical (y) axis. It's a uniform motion on the x-axis, with constant speed

, and an accelerated motion on the y-axis, with initial speed

and acceleration

:


where the negative sign in front of g means the acceleration points towards negative direction of y-axis (downward).
To find the distance from the landing point, we should find first the time at which the projectile hits the ground. This can be found by requiring

Therefore:

which has two solutions:

is the time of the beginning of the motion,

is the time at which the projectile hits the ground.
Now, we can find the distance covered on the horizontal axis during this time, and this is the distance from launching to landing point:
Question: Which of the following is true about scientific models? Select one: A) Models are used to simplify the study of things. B) Computer models are the most reliable kind of model. C) Models explain past, present and future information. D) A model is accurate if it does not change over time.
Answer: <u>A) Models are used to simplify the study of things.</u>
<em>Hope this helps!.</em>
<em>~~~~~~~~~~~~~~~~~~~~~~</em>
<em>~A.W~ZoomZoom44</em>
Answer:
Potential energy is 
Explanation:
The potential energy depends on the mass, the acceleration of gravity g and the height at which the object or person is.
Potential energy 
In this case we would need to know the exact mass of the hiker in order to calculate the potential energy.
But we know the values of g and h


So, the potential energy

m is the mass of the hiker, wich is not in the description of the problem.