This question can be solved by using the equations of motion.
a) The initial speed of the arrow is was "9.81 m/s".
b) It took the arrow "1.13 s" to reach a height of 17.5 m.
a)
We will use the second equation of motion to find out the initial speed of the arrow.

where,
vi = initial speed = ?
h = height = 35 m
t = time interval = 2 s
g = acceleration due to gravity = 9.81 m/s²
Therefore,

<u>vi = 9.81 m/s</u>
b)
To find the time taken by the arrow to reach 17.5 m, we will use the second equation of motion again.

where,
g = acceleration due to gravity = 9.81 m/s²
h = height = 17.5 m
vi = initial speed = 9.81 m/s
t = time = ?
Therefore,

solving this quadratic equation using the quadratic formula, we get:
t = -3.13 s (OR) t = 1.13 s
Since time can not have a negative value.
Therefore,
<u>t = 1.13 s</u>
Learn more about equations of motion here:
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The attached picture shows the equations of motion in the horizontal and vertical directions.
Answer:
Choices A, B, and C are correct.
Explanation:
Let us look at each of the choices one by one:
A. It is a vector
Yes. Velocity is a vector, or it's a speed with direction.
B. It is the change in displacement divided by the change in time.
Yes. The velocity can be written as

where
is the displacement—a vector quantity.
C. It can be measured in meters per second.
Yes. The units of velocity are m/s, but also with a unit vector indicating the direction.
D. It is the slope of the acceleration vs. time graph.
Nope. The velocity is the slope of displacement vs. time graph.
Hence, only choices A, B, and C are correct.
Answer:
See explanation
Explanation:
Acids and bases contain ions that interact with water. According to the Arrhenius definition, acids are substances that produce hydrogen ion in water while bases are substances that produce hydroxide ion in water.
The pH scale is a graphic description of the hydrogen or hydroxide ion present in a sample. Since pH= -log[H^+], the higher the pH , the lower the hydrogen ion concentration and vice versa.
Similarly, pOH= -log [OH^-] , hence the more the OH^- concentration the lower the pOH.
However pH + pOH =14.
Thus the concentration of hydrogen or hydroxide ions present determines the pH of any solution.
Answer:
speed = 20 m/s
Explanation:
speed = frequency * wavelength
speed = 4 * 5
speed = 20 m/s
North, East, South, West (in order)