Answer:
<em>1.01 W/m</em>
Explanation:
diameter of the pipe d = 30 mm = 0.03 m
radius of the pipe r = d/2 = 0.015 m
external air temperature Ta = 20 °C
temperature of pipe wall Tw = 150 °C
convection coefficient at outer tube surface h = 11 W/m^2-K
From the above,<em> we assumed that the pipe wall and the oil are in thermal equilibrium</em>.
area of the pipe per unit length A = 
= 
m^2/m
convectional heat loss Q = Ah(Tw - Ta)
Q = 7.069 x 10^-4 x 11 x (150 - 20)
Q = 7.069 x 10^-4 x 11 x 130 = <em>1.01 W/m</em>
Answer:
Explanation:
Given a parallel plate capacitor of
Area=A
Distance apart =d
Potential difference, =V
If the distance is reduce to d/2
What is p.d
We know that
Q=CV
Then,
V=Q/C
Then this shows that the voltage is inversely proportional to the capacitance
Therefore,
V∝1/C
So, VC=K
Now, the capacitance of a parallel plate capacitor is given as
C= εA/d
When the distance apart is d
Then,
C1=εA/d
When the distance is half d/2
C2= εA/(d/2)
C2= 2εA/d
Then, applying
VC=K
V1 is voltage of the full capacitor V1=V
V2 is the required voltage let say V'
Then,
V1C1=V2C2
V × εA/d=V' × 2εA/d
VεA/d = 2V'εA/d
Then the εA/d cancels on both sides and remains
V=2V'
Then, V'=V/2
The potential difference is half when the distance between the parallel plate capacitor was reduce to d/2
Answer:
0.34
Explanation:
2.5 Mg = 2500 kg
The change in speed from 100 km/h to 40 km/h is
The deceleration caused by friction force is the change in speed per unit of time
Using Newton 2nd law we can calculate the friction force that caused this deceleration:
F = ma = 2500 * 3.33 = 8333 N
Let g = 9.8m/s2. Friction force is the product of normal (gravity) force and friction coefficient
The frequency of any wave is (wave speed) / (wavelength) .
The speed of light is 3 x 10⁸ m/s.
If the wavelength is 10 nm (10⁻⁸ m) , then the frequency is
(3 x 10⁸) / (10⁻⁸) = <em>3 x 10¹⁶ Hz</em>
That's 30 million gigahertz !
Answer:
the hypothalamus part of your brain sends a message to your body telling it to sweat.
When your internal temperature rises, your sweat glands release water to the surface of your skin.
