Answer: 17.68 s
Explanation:
This problem is a good example of Vertical motion, where the main equation for this situation is:
(1)
Where:
is the height of the ball when it hits the ground
is the initial height of the ball
is the initial velocity of the ball
is the time when the ball strikes the ground
is the acceleration due to gravity
Having this clear, let's find
from (1):
(2)
Rewritting (2):
(3)
This is a quadratic equation (also called equation of the second degree) of the form
, which can be solved with the following formula:
(4)
Where:



Substituting the known values:
(5)
Solving (5) we find the positive result is:

Answer:
15m/s
Explanation:
add the two speeds and divide by 2
10+20=30
30/2=15
Answer:
B. convergent boundary
Explanation:
Convergent boundaries, where ocean plates are subducted at trenches, produce the most tsunamis because they produce the largest earthquakes
<span>The correct frequency when you tune a guitar is
when you hear the right tune in your own hearing and standard. The measure
frequency of a guitar string is when you measure the tune of the string
correctly. This is not the same because manual tuning is affected by many
factors.</span>