10. A rollercoaster reaches a top speed of 117 km/hr. Its initial (and tallest)
descent can be modeled by h(t) = 81–4.9t2 , where h is in meters and
t is in seconds. Use this information to solve the following questions:
a How long before the roller coaster reaches the ground?
b) What is the height of the roller coaster just before it begins its decent?
c) Draw a graph to show the decent of the rollercoaster. Include the
coordinate points of the x and y axis.

help!

a) 4.07 s

b) 81 m

Step-by-step explanation:

a)

h(t) = 0 at full descent.

81 - 4.9t^2 = 0

4.9t^2 = 81

t^2 = 81/4.9

t = 4.07

4.07 s

b)

Initial height is at t = 0.

h(0) = 81 - 4.9(0)^2

h(0) = 81

81 m

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

what statement? is there an image?