*Solution:*
*Part 1:*

The first quantity appearing in the reduction of the problem is
...moving at 12 m/s... present in the first
sentence. *The words "moving at" mean
velocity even when in the same sentence the words "acceleration
ramp" is present. Notice that "moving at"
is used in the sentence as part of the verb conjugation while "acceleration
ramp" is an adjective-noun combination.* Another direct form
of identifying this quantity as a velocity is to recognize the unit of
the number, m/s, as the basic unit of
velocity in the metric system. In the last sentence of the redaction of
the problem, the word after appears
indicating that there is a time sequence in this problem. Because the 12
m/s is the entering velocity into the ramp, this velocity is an initial
velocity. Thus,

*v*_{0} = 12 m/s

The second quantity presented in the problem is 1.5 m/s^{2}.
Because this quantity is presided by the words "accelerate
at the rate of" this quantity is the acceleration. This quantity
can also be identified as an acceleration when the units used are
recognized as the standard units of acceleration in the metric system.
Thus,

*a* = 1.5 m/s^{2}

The third quantity is ... for 4 seconds....
This quantity is repeated a fourth time in the last sentence as "After
the 4 seconds" where the sequential use of this quantity can be
concluded from the word after. Also, the
unit of this quantity is one of the most common units of time, the
second. Therefore,

*t* = 4 s.

The previous analysis complete the identification of the known data of
the problem. The next step is to identified the required result and the
unknown associated with it. The question asks specifically for the
merging velocity of the car. Thus, the
unknown is the velocity. Additionally, the last sentence of the
redaction of the problem clearly indicate that the merging occurs
after which identifies this velocity
as the final velocity. Thus,

*v* = ?

By comparing the known and unknown quantities with the variables
appearing in the
five formulas for this motion, the following can be concluded:

Formulas (U_A_M 1),
, and (U_A_M
2),
, can be eliminated as possible formulas for obtaining the
solution because, in this problem, there is not known and unknown
quantity that deals with average velocity. However, formula (U_A_M
3),
, includes as part of the variables each of the known quantities
presented in this problem. In addition, the unknown of this problem is
the result of formula (U_A_M 3). Therefore,
the solution to this problem is obtained from
.

Substituting the known values in this formula, *
v* = 12 m/s + (1.5 m/s^{2})(4
s) = 12 m/s + 6 m/s = 18 m/s. Therefore, the final velocity is *
v* = 18 m/s.

*Part 1:*

To
respond to this question, it is necessary to write the previous velocity
in Mi/H. For this effect, the equivalence between the mile and kilometer
is 1 Mi =1.609 Km with 1 Km = 1000 m. Therefore,

1 Mi
= 1609 m which implies that 1m = 1/1609 Mi

At
the same time, 1 H = 60 Min with 1 Min = 60 s. Thus,

1
H = 60 × 60 s = 3600 s which implies
that 1 s = 1/3600 H. Putting together these two results,

The difference between the
speed limit and the merging speed of the car is not obtained from one of
the formulas for uniformed accelerated motion. However, the word
difference means that for obtaining this result, it is necessary to
subtract the smaller quantity from the larger, 60 Mi/H - 40 Mi/H = 20
Mi/H. Notice that the merging velocity has been rounded to the nearest
integer.