Answer: 
Explanation:
In the image attached with this answer are shown the given options from which only one is correct.
The correct expression is:

Because, if we derive velocity
with respect to time
we will have acceleration
, hence:

Where
is the mass with units of kilograms (
) and
with units of meter per square seconds
, having as a result 
The other expressions are incorrect, let’s prove it:
This result has units of
This result has units of
This result has units of
and
is a constant
This result has units of
This result has units of
This result has units of
and
is a constant
This result has units of
and
is a constant
because
is a constant in this derivation respect to
This result has units of
and
is a constant
Does it not tell you how long it took it to reach the ground? Constant Velocity should be distance over time
Let the height where we are trapped is H
now to find the time to reach the key at the bottom is given as

now we have


now if the speed of sound is considered to be 340 m/s then time taken by the sound to reach at the top is given as

now the total time is given as

now by solving above equation we have
H = 48 m
now height of one floor is 3 m
so our position must be

Answer: <em>Around each new moon and full moon, the sun, Earth, and moon arrange themselves more or less along a line in space. Then the pull on the tides increases, because the gravity of the sun reinforces the moon's gravity. ... This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season.</em>
Answer:
happier; do not
Explanation:
A major physical disability usually leaves people __happier______ than able-bodied people with depression. Most patients "locked-in" a motionless body ____do not____ indicate they want to die.