In refraction, when a wave travels from one medium to another it changes speed.
Correct option is A.
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Answer:
Max speed = 
Max acceleration = 
Explanation:
Given the description of period and amplitude, the SHM could be described by:

and its angular velocity can be calculated doing the derivative:

And therefore, the tangential velocity is calculated by multiplying this expression times the radius of the movement (3 m):
and is given in m/s.
Then the maximum speed is obtained when the cosine function becomes "1", and that gives:
Max speed = 
The acceleration is found from the derivative of the velocity expression, and therefore given by:

and the maximum of the function will be obtained when the sine expression becomes "-1", which will render:
Max acceleration = 
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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