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/ $s^2$