The answer is A. Opposites attract, hence the attraction during friction. Balloons and hair would be a great example.
Explanation:
Technology-based:
1.As the name implies technology, no technology will be clarified about it. It only depends on the variables, which describes them.
2. That is based on a single facility's findings.
3. It takes into account the contaminants type and volume, and their equations to monitor them.
4. This is reserved for city or urban wastewater treatment plants only.
5. It takes into account the pH, need for oxygen and the suspended solids.
Water quality based on:
1.This is enforced if there is a need to apply stricter limits to pollutants that are not pleased with the limits of technology.
2. All basing on water quality was risk-based.
3. They placed some less importance on the technologies which is used in the technology based limit.
Water quality dependent restrictions are used as cool water fishery for streams.
The act on clean water will also include bodies of water belonging to wildlife, agriculture and others. The law also included that the physical chemical and biological variables of all the state water bodies must be controlled by these water quality based limits.
Answer:
A) amps using an ammeter.....
Answer:
is the final velocity of the racket.
![F=18.86\ N](https://tex.z-dn.net/?f=F%3D18.86%5C%20N)
Explanation:
Given:
- mass of the racket,
![m_r=1000\ g](https://tex.z-dn.net/?f=m_r%3D1000%5C%20g)
- mass of ball,
![m_b=60\ g](https://tex.z-dn.net/?f=m_b%3D60%5C%20g)
- initial speed of racket,
![u_r=15\ m.s^{-1}](https://tex.z-dn.net/?f=u_r%3D15%5C%20m.s%5E%7B-1%7D)
- initial speed of ball,
![u_b=18\ m.s^{-1}](https://tex.z-dn.net/?f=u_b%3D18%5C%20m.s%5E%7B-1%7D)
- final speed of ball,
![v_b=40\ m.s^{-1}](https://tex.z-dn.net/?f=v_b%3D40%5C%20m.s%5E%7B-1%7D)
- time of contact of racket with the ball,
![t=0.07\ s](https://tex.z-dn.net/?f=t%3D0.07%5C%20s)
<u>By the law of conservation of momentum:</u>
![m_r.u_r+m_b.u_b=m_r.v_r+m_b.v_b](https://tex.z-dn.net/?f=m_r.u_r%2Bm_b.u_b%3Dm_r.v_r%2Bm_b.v_b)
where:
final velocity of the racket
![1000\times 15+60\times 18=1000\times v_r+60\times 40](https://tex.z-dn.net/?f=1000%5Ctimes%2015%2B60%5Ctimes%2018%3D1000%5Ctimes%20v_r%2B60%5Ctimes%2040)
is the final velocity of the racket.
<u>By the Newton's second law of motion:</u>
............................(1)
where:
dp = change in momentum
dt = change in time
Change in momentum of ball:
![\Delta p_b=m_b.v_b-m_b.u_b](https://tex.z-dn.net/?f=%5CDelta%20p_b%3Dm_b.v_b-m_b.u_b)
![\Delta p_b=60\times 10^{-3}\times (40-18)](https://tex.z-dn.net/?f=%5CDelta%20p_b%3D60%5Ctimes%2010%5E%7B-3%7D%5Ctimes%20%2840-18%29)
![\Delta p_b=1.32\ kg.m.s^{-1}](https://tex.z-dn.net/?f=%5CDelta%20p_b%3D1.32%5C%20kg.m.s%5E%7B-1%7D)
Now, using eq.(1):
![F=\frac{1.32}{0.07}](https://tex.z-dn.net/?f=F%3D%5Cfrac%7B1.32%7D%7B0.07%7D)
![F=18.86\ N](https://tex.z-dn.net/?f=F%3D18.86%5C%20N)
Yesss!!!!!!!!!!!!
Earth does have magnetic variation