Answer:

Explanation:
The angular frequency of the system is:

The frequency is:


The angular frequency is:


The spring constant is:


Work = (force) x (distance
28.4 joules = (force) x (4 meters)
Divide each side by (4 meters) :
Force = (28.4 joules) / (4 meters)
Force = 7.1 Newtons
If I did my math right I believe 13 is the 9.3 seconds and 14 is the first option because of logic. The question basically says, how does the height change and the answer is the first one because it gets higher then lower, or increases then decreases.
Answer: D. 25 m/s Downward
Explanation:
V = (g)(t)
V = (9.8 m/s²)(2.5)
V = 24.5 m/s
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