Answer:
1) ![\sum \vec p=0\ kg.m.s^{-1}](https://tex.z-dn.net/?f=%5Csum%20%5Cvec%20p%3D0%5C%20kg.m.s%5E%7B-1%7D)
2) ![v_2=55.078\ m.s^{-1}](https://tex.z-dn.net/?f=v_2%3D55.078%5C%20m.s%5E%7B-1%7D)
Explanation:
Given:
- mass of heavier student,
![m_1=95\ kg](https://tex.z-dn.net/?f=m_1%3D95%5C%20kg)
- mass of lighter student,
![m_2=58\ kg](https://tex.z-dn.net/?f=m_2%3D58%5C%20kg)
- velocity of the heavier student after the mutual push,
![v_1=3.1\ m.s^{-1}](https://tex.z-dn.net/?f=v_1%3D3.1%5C%20m.s%5E%7B-1%7D)
1)
Since they push each other and we are neglecting any friction that means we can consider this as a perfectly elastic collision. So the momentum of the two bodies will be equal and in opposite direction.
Since momentum is a vector quantity so the total momentum of the system as a whole will be zero.
2)
<u>From the condition of elastic collision:</u>
![p_1=p_2](https://tex.z-dn.net/?f=p_1%3Dp_2)
![m_1.v_1=m_2.v_2](https://tex.z-dn.net/?f=m_1.v_1%3Dm_2.v_2)
![95\times 3.1=58\times v_2](https://tex.z-dn.net/?f=95%5Ctimes%203.1%3D58%5Ctimes%20v_2)
![v_2=55.078\ m.s^{-1}](https://tex.z-dn.net/?f=v_2%3D55.078%5C%20m.s%5E%7B-1%7D)
The answer is to maintain safety.
Given Information:
Inlet Temperature of hot air= Th₁ = 450K
Exit Temperature of hot air = Th₂ = 350K
Inlet Temperature of cold air = Tc₁ = 300K
Volume flow rate of hot air = vh = 0.02 m³/s
Volume flow rate of cold air = vc = 1 m³/s
Required Information:
Exit Temperature of cold air= Tc₂ = ?
Answer:
Exit Temperature of cold air = Tc₂ = 302 °C
Explanation:
In a heat exchanger, the cold air absorbs heat that is lost by the hot air,
Heat absorbed by cold air = Heat lost by hot air
![m_{c}\cdot c_{p}(T_{c2} -T_{c1} ) = m_{h}\cdot c_{p}(T_{h1} -T_{h2})\\m_{c}(T_{c2} -T_{c1} ) = m_{h}(T_{h1} -T_{h2})\\\rho\dot{v_{c}}(T_{c2} -T_{c1} ) =\rho\dot{v_{h}} (T_{h1} -T_{h2})\\\dot{v_{c}}(T_{c2} -T_{c1} ) =\dot{v_{h}} (T_{h1} -T_{h2})\\1 \cdot(T_{c2} -300 ) =0.02\cdot (450 -350)\\(T_{c2} -300 ) =0.02\cdot (100)\\(T_{c2} -300 ) =2\\T_{c2} =2 + 300 \\T_{c2} = 302](https://tex.z-dn.net/?f=m_%7Bc%7D%5Ccdot%20c_%7Bp%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%20m_%7Bh%7D%5Ccdot%20c_%7Bp%7D%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5Cm_%7Bc%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%20m_%7Bh%7D%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C%5Crho%5Cdot%7Bv_%7Bc%7D%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%5Crho%5Cdot%7Bv_%7Bh%7D%7D%20%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C%5Cdot%7Bv_%7Bc%7D%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%5Cdot%7Bv_%7Bh%7D%7D%20%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C1%20%5Ccdot%28T_%7Bc2%7D%20-300%20%29%20%3D0.02%5Ccdot%20%28450%20-350%29%5C%5C%28T_%7Bc2%7D%20-300%20%29%20%3D0.02%5Ccdot%20%28100%29%5C%5C%28T_%7Bc2%7D%20-300%20%29%20%3D2%5C%5CT_%7Bc2%7D%20%20%3D2%20%2B%20300%20%5C%5CT_%7Bc2%7D%20%20%3D%20302)
Therefore, the exit temperature of the cold air is 302 °C or 575K
Note:
m = ρv
Where ρ is density of air and v is the volume flow rate and m is the mass flow rate.
cp is the specific heat capacity of air.
Answer:
his speed is 5cm a second
Opposition for the current flow
Explanation:
- Resistance is defined as the ability pf the conductor to oppose the flow of electrons through it. It is usually represented in Ohm.
- Resistance is an important parameter in a circuit design and it should be properly designed.
- Resistance of a conductor depends upon the material nature, length of the conductor and area of cross section.
- In conductor, Resistance is low. It is due to that charges flow through the conductor freely.