Answer:
6.21 seconds
Step-by-step explanation:
The position function of a free-falling object is,
Where,
= initial height of the object,
= initial velocity of the object,
Here,
Hence, the height of the ball after t seconds,
When s(t) = 0,
∵ Time cannot be negative,
Hence, after 6.21 seconds the ball will reach the ground.
Answer:
45 minutes is 3/4 of an hour, so find 3/4 of 12.
Divide 12 by 4 to get 1/4 of 12. That is 3.
3/4 is 3 of those, so multiply it by 3 to get 9.
So, she will have biked 9 miles.
Answer:
60
Step-by-step explanation:
sum the parts of the ratio, 8 + 12 = 20 parts
Divide the total by 20 to find the value of one part of the ratio
100 ÷ 20 = 5 ← value of 1 part of the ratio , thus
8 parts = 8 × 5 = 40 ← number of purple bikes
First, we have to convert our function (of x) into a function of y (we revolve the curve around the y-axis). So:
And the derivative of x:
Now, we can calculate the area of the surface:
We could calculate this integral (not very hard, but long), or use
(1),
(2) and
(3) to get:
Calculate indefinite integral:
And the area:
![A=2\pi\int\limits_0^{10}x\sqrt{4x^2+1}\,dx=2\pi\cdot\dfrac{1}{12}\bigg[\left(4x^2+1\right)^\frac{3}{2}\bigg]_0^{10}=\\\\\\= \dfrac{\pi}{6}\left[\big(4\cdot10^2+1\big)^\frac{3}{2}-\big(4\cdot0^2+1\big)^\frac{3}{2}\right]=\dfrac{\pi}{6}\Big(\big401^\frac{3}{2}-1^\frac{3}{2}\Big)=\boxed{\dfrac{401^\frac{3}{2}-1}{6}\pi}](https://tex.z-dn.net/?f=A%3D2%5Cpi%5Cint%5Climits_0%5E%7B10%7Dx%5Csqrt%7B4x%5E2%2B1%7D%5C%2Cdx%3D2%5Cpi%5Ccdot%5Cdfrac%7B1%7D%7B12%7D%5Cbigg%5B%5Cleft%284x%5E2%2B1%5Cright%29%5E%5Cfrac%7B3%7D%7B2%7D%5Cbigg%5D_0%5E%7B10%7D%3D%5C%5C%5C%5C%5C%5C%3D%20%5Cdfrac%7B%5Cpi%7D%7B6%7D%5Cleft%5B%5Cbig%284%5Ccdot10%5E2%2B1%5Cbig%29%5E%5Cfrac%7B3%7D%7B2%7D-%5Cbig%284%5Ccdot0%5E2%2B1%5Cbig%29%5E%5Cfrac%7B3%7D%7B2%7D%5Cright%5D%3D%5Cdfrac%7B%5Cpi%7D%7B6%7D%5CBig%28%5Cbig401%5E%5Cfrac%7B3%7D%7B2%7D-1%5E%5Cfrac%7B3%7D%7B2%7D%5CBig%29%3D%5Cboxed%7B%5Cdfrac%7B401%5E%5Cfrac%7B3%7D%7B2%7D-1%7D%7B6%7D%5Cpi%7D)
Answer D.
