This is something u are going to have to do
Answer:The correct options are:
1. A system is a group of objects analyzed as one unit.
2. Energy that moves across system boundaries is conserved.
Explanation:
A system is defined as group of interrelated or interacting items existing as a single unit or a whole to achieve a specific objective.Energy lost by the system is equal to the energy gained by the surroundings.
Two statements are true about a system:
- A system is a group of objects analyzed as one unit.
- Energy that moves across system boundaries is conserved.
Answer:
Temperature decreases because the number of collision of the molecules decreases as they escape or evaporate. Molecules are in constant motion. Increase in temperature leads to increase in average kinetic energy of the molecules.
Answer:
![V(t)= 240V* H(t-5)](https://tex.z-dn.net/?f=V%28t%29%3D%20240V%2A%20H%28t-5%29)
Explanation:
The heaviside function is defined as:
![H(t) =1 \quad t\geq 0\\H(t) =0 \quad t](https://tex.z-dn.net/?f=H%28t%29%20%3D1%20%5Cquad%20t%5Cgeq%200%5C%5CH%28t%29%20%3D0%20%5Cquad%20t%20%3C0)
so we see that the Heaviside function "switches on" when
, and remains switched on when ![t>0](https://tex.z-dn.net/?f=t%3E0)
If we want our heaviside function to switch on when
, we need the argument to the heaviside function to be 0 when ![t=5](https://tex.z-dn.net/?f=t%3D5)
Thus we define a function f:
![f(t) = H(t-5)](https://tex.z-dn.net/?f=f%28t%29%20%3D%20H%28t-5%29)
The
term inside the heaviside function makes sure to displace the function 5 units to the right.
Now we just need to add a scale up factor of 240 V, because thats the voltage applied after the heaviside function switches on. (
when
, so it becomes just a 1, which we can safely ignore.)
Therefore our final result is:
![V(t)= 240V* H(t-5)](https://tex.z-dn.net/?f=V%28t%29%3D%20240V%2A%20H%28t-5%29)
I have made a sketch for you, and added it as attachment.
Since Astronaut and wrench system is isolated in the space and there is no external force on it
So here momentum of the system will remain conserved
so here we can say
![m_1v_{1i} + m_2v_{2i} = m_1v_{1f} + m_2v_{2f}](https://tex.z-dn.net/?f=m_1v_%7B1i%7D%20%2B%20m_2v_%7B2i%7D%20%3D%20m_1v_%7B1f%7D%20%2B%20m_2v_%7B2f%7D)
initially both are at rest
so here plug in all values
![0 = 100 v_{1f} + 2\times 10](https://tex.z-dn.net/?f=0%20%3D%20100%20v_%7B1f%7D%20%2B%202%5Ctimes%2010)
![v_{1f} = -0.20 m/s](https://tex.z-dn.net/?f=v_%7B1f%7D%20%3D%20-0.20%20m%2Fs)
so here the astronaut will move in opposite direction and its speed will be equal to 0.20 m/s