Answer: The value of u · d = 4
Explanation:
(2y -1) = 0 , 2y = 1 , y = 1/2 . u = 1/2
(8-y)=0 y = 8 d = 8
Substitute values for u·d 1/2 · 8 = 4
Answer:
Yesss I want the answer key
The way in which Europeans in the late nineteenth century attempted to transform the point of view expressed is the fact that they believe the presence of British residents, the set up of hotels and tour guides and the building of house to transform the historical reality of Africa.
<h3>What transformations is seen in Africa in the 19th century?</h3>
The 19th century was known to be a time of revolutionary period for European history.
Africa during the 19th century was known to be a time where there was the European colonization of the continent.
There was tremendous growth and also a lot of innovation in majority of African political and economic institutions.
Learn more about Africa from
brainly.com/question/25110079
Answer:
Ang panahon o kalagayan ng panahon ay ang paglalarawan sa kalagayan at katangiang pangkalikasan sa labas ng tahanan, gusali o anumang tirahan ng tao, hayop, halaman at iba pang mga nilalang, na ayon sa singaw ng kalawakan o ng atmospera ng daigdig. Tumutukoy ito sa kainitan, katuyuan, kalamigan, kabasaan, katahimikan, pagka-maaraw, pagkamahangin, o pagiging maulan sa isang pook, sa isang takdang oras, na maaaring magbago. Nararamdaman, naririnig, nakikita ng tao ang epekto ng panahon at maging ang pagbabago sa kalagayan nito. Nasusukat din ang panahon sa pamamagitan ng mga termometro, barometro, barograpo, sikrometro o higrometro, panukat ng hangin, anemometro, at mga panukat ng ulan. Depende rin ang taya ng panahon sa pagdating ng kapanahunan ng tag-init, taglamig, taglagas, tagsibol at tag-ulan.[1]
Answer:
![v_s=0\ km/h](https://tex.z-dn.net/?f=v_s%3D0%5C%20km%2Fh)
![v_s=3\ km/h](https://tex.z-dn.net/?f=v_s%3D3%5C%20km%2Fh)
Explanation:
<u>Relative Speed
</u>
A boat traveling in still waters has a speed v_b. If now an opposite stream appears, then the apparent speed of the boat will be less than before because the relative speed is the subtraction of both speeds. Thus we say
![v_{t1}=v_b-v_s](https://tex.z-dn.net/?f=v_%7Bt1%7D%3Dv_b-v_s)
Conversely, if the stream goes with the boat, both speeds are added.
![v_{t2}=v_b+v_s](https://tex.z-dn.net/?f=v_%7Bt2%7D%3Dv_b%2Bv_s)
where
it the total or real speed of the boat respect to the ground,
is the speed of the boat in still water, and
is the speed of the stream.
The boat goes 36 km with stream. The time it took for doing so is:
![\displaystyle t_1=\frac{36}{v_b+v_s}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20t_1%3D%5Cfrac%7B36%7D%7Bv_b%2Bv_s%7D)
The boat goes 24 km against the stream in
![\displaystyle t_2=\frac{24}{v_b-v_s}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20t_2%3D%5Cfrac%7B24%7D%7Bv_b-v_s%7D)
The problem states that
![t_1+t_2=4\ hours](https://tex.z-dn.net/?f=t_1%2Bt_2%3D4%5C%20hours)
![\displaystyle \frac{36}{v_b+v_s}+\frac{24}{v_b-v_s}=4](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B36%7D%7Bv_b%2Bv_s%7D%2B%5Cfrac%7B24%7D%7Bv_b-v_s%7D%3D4)
Knowing ![v_b=15](https://tex.z-dn.net/?f=v_b%3D15)
![\displaystyle \frac{36}{15+v_s}+\frac{24}{15-v_s}=4](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B36%7D%7B15%2Bv_s%7D%2B%5Cfrac%7B24%7D%7B15-v_s%7D%3D4)
Operating
![\displaystyle 36(15-v_s)+24(15+v_s)=4(15+v_s)(15-v_s)](https://tex.z-dn.net/?f=%5Cdisplaystyle%2036%2815-v_s%29%2B24%2815%2Bv_s%29%3D4%2815%2Bv_s%29%2815-v_s%29)
Rearranging and simplifying
![225-3v_s=225-v_s^2](https://tex.z-dn.net/?f=225-3v_s%3D225-v_s%5E2)
Factoring
![v_s(v_s-3)=0)](https://tex.z-dn.net/?f=v_s%28v_s-3%29%3D0%29)
We get
![v_s=0,\ v_s=3](https://tex.z-dn.net/?f=v_s%3D0%2C%5C%20v_s%3D3)
Both solutions are possible, i.e.
1. The stream does not exist and the boat travels the total distance of 60 Km in 4 hours
2. The stream has a speed of 3 Km/h and the boat travels 36 km in 2 hours and 24 km in 2 hours