Answer:
a)=251.2 cm b)=50240 cm
Step-by-step explanation:
a) The formula for calculating the circumference of a circle is c=d*pie, where D is the diameter of the circle.
Therefore, C = 2 * 40 * 3.14 = 251.2 cm
b) The distance covered by 200 revolutions of the wheel is 200 times the circumference, 200*251.2=50240 cm.So to think about this we can assume that there is a point A on the wheel, the distance that point A travels when it rotates 200 times.
Y1 is the simplest parabola. Its vertex is at (0,0) and it passes thru (2,4). This is enough info to conclude that y1 = x^2.
y4, the lower red graph, is a bit more of a challenge. We can easily identify its vertex, which is (-4,0), and several points on the grah, such as (2,-3).
Let's try this: assume that the general equation for a parabola is
y-k = a(x-h)^2, where (h,k) is the vertex. Subst. the known values,
-3-(-4) = a(2-0)^2. Then 1 = a(2)^2, or 1 = 4a, or a = 1/4.
The equation of parabola y4 is y+4 = (1/4)x^2
Or you could elim. the fraction and write the eqn as 4y+16=x^2, or
4y = x^2-16, or y = (1/4)x - 4. Take your pick! Hope this helps you find "a" for the other parabolas.
