If a rock is thrown upward on the planet Mars with a velocity of , its height in meters t seconds later is given by . Find the average velocity over the time interval .
A) m/s
B) m/s
C) m/s
D) m/s
E) m/s

Question

If a rock is thrown upward on the planet Mars with a velocity of  , its height in meters t seconds later is given by  . Find the average velocity over the time interval  .
A) m/s 
B) m/s 
C) m/s 
D) m/s 
E) m/s

Quizplus · Accepted Answer

The average velocity over a time interval is given by (change in position) / (change in time). In this case, the position function is given by h(t) = -0.327t^2 + 84.78t, so the change in position over the time interval [16,20] is:
h(20) - h(16) = (-0.327(20)^2 + 84.78(20)) - (-0.327(16)^2 + 84.78(16))
= 15.18 meters

The change in time is:
20 - 16 = 4 seconds

So the average velocity is:
(15.18 m) / (4 s) = 3.795 m/s

Using scientific notation, this is equivalent to:
Answer: C
 The average velocity is 3.795 m/s. This is closest to choice (C) 11eaa3e5_5620_7f71_9f8f_898ed45d6408_TB5971_11 m/s when rounded to two decimal places.

If a Rock Is Thrown Upward on the Planet Mars