Question #43247

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Answer 1 · 2017-10-13T13:17:38

#a = 6 m/s^2#

The formula relating velocity under constant acceleration is:

#v_f = v_i + at#

Each variable, and the known values for this problem, are shown below:

#{(v_f, "Final velocity", 22 m/s) , (v_i, "Initial velocity", 4 m/s), (a, "Acceleration", "?"), (t, "Time", 3 s) :} #

Substituting into the formula:

#22 m/s = 4 m/s + a(3 s)#

#18 m/s = a(3 s)#

#6 m/s^2 = a#

Answer 2 · 2017-10-13T13:24:07

#a = 6#m/#s^2#

The velocity when roller coaster starts down the slope is #4#m/#s#.
That is, it's initial velocity is #4#m/#s#, i.e., #u = 4#

After #t = 3s# the velocity a the bottom is #22#m/#s#.
That is, it's final velocity is #22#m/#s#, i.e., #v = 4#

Using formula,
#v = u + at#
#22 = 4 + 3a#

#a = 6#m/#s^2#