Since you didn't give an amount of time, we can't give an exact value. However, I can help you with the steps so you can get the correct answer.
First, you need to find the correct z-score. Then, use a standard normal distribution table to find the percent.
Let the time that you are looking for equal X.
The formula for your z-score is:
(x - 8.7) / 2.1 = z-score
Answer:
s = 6 m
Step-by-step explanation:
The value of the velocity v is given as:
m/s
To find s, we have to integrate and apply the initial values of s = o when t = 0:

When t = π/2, s will be:
s = -3cos(2 * π/2) + 3
s = -3cos(π) + 3
s = -3(-1) + 3
s = 3 + 3
s = 6 m
Standard equation for a circle is: (x -h)² + (y - k)² = r²
(h,k) is the center which is given to be: (0,0) so you just need the radius.
The radius is the distance from the center to the point (-4,5) on the edge.
Use the distance formula
d = √[(-4 - 0)² + (5 -0)²]
d = √[16 + 25]
d = √[41]
radius is √[41]
so the equation for the circle is: x² + y² = 41
1/4 converted into a decimal is .25
20÷.25=80
the answer is 80