This question is in regards to grade 12 advanced function - specifically in the unit/subject of average rate of change and instantaneous rate of change.
Ok, so I am prepping for a final exam and the course I am taking offers practice exams with answers.
The question was:
A ball is tossed in the air on the planet Mars. It's height is modeled by h=-1.85(t-4)^2+31
a. Determine the maximum height of the ball
b. What velocity will the ball be travelling at when it hits the ground?
My answer:
a. 31
b.
-1.85(t-4)^2 +31 = 0
-1.85(t-4)^2 = -31
etc etc etc....
t=8.09
(8.09,0)
velocity = (-.0985 - .20416) / (8.1-8.08)
= -15.133
Therefore, the ball is moving downwards at 15.133 m/s.
Confirmed with first derivative
h=-1.85(t-4)^2+31
h' = -3.7(t-4)
= -3.7(8.09-4)
= -15.133
Hopefully you can see the picture as this is what their answer was. Makes no sense to me whatsoever what they did. Hopefully someone can explain....
Ok, so I am prepping for a final exam and the course I am taking offers practice exams with answers.
The question was:
A ball is tossed in the air on the planet Mars. It's height is modeled by h=-1.85(t-4)^2+31
a. Determine the maximum height of the ball
b. What velocity will the ball be travelling at when it hits the ground?
My answer:
a. 31
b.
-1.85(t-4)^2 +31 = 0
-1.85(t-4)^2 = -31
etc etc etc....
t=8.09
(8.09,0)
velocity = (-.0985 - .20416) / (8.1-8.08)
= -15.133
Therefore, the ball is moving downwards at 15.133 m/s.
Confirmed with first derivative
h=-1.85(t-4)^2+31
h' = -3.7(t-4)
= -3.7(8.09-4)
= -15.133
Hopefully you can see the picture as this is what their answer was. Makes no sense to me whatsoever what they did. Hopefully someone can explain....