Answer:
Option C (80 ohms) is the right answer.
Explanation:
The given values are:
Current,
I = 1.5 A
Voltage,
V = I20 V
As we know,
⇒ ![V=IR](https://tex.z-dn.net/?f=V%3DIR)
or,
The resistance will be:
⇒ ![R=\frac{V}{I}](https://tex.z-dn.net/?f=R%3D%5Cfrac%7BV%7D%7BI%7D)
On substituting the values, we get
⇒ ![=\frac{120}{1.5}](https://tex.z-dn.net/?f=%3D%5Cfrac%7B120%7D%7B1.5%7D)
⇒ ![=80 \ ohms](https://tex.z-dn.net/?f=%3D80%20%5C%20ohms)
Answer:
a. Heat removal rate will increase
b. Heat removal rate will decrease
Explanation:
Given that
One end of rod is connected to the furnace and rod is long.So this rod can be treated as infinite long fin.
We know that heat transfer in fin given as follows
![Q_{fin}=\sqrt{hPKA}\ \Delta T](https://tex.z-dn.net/?f=Q_%7Bfin%7D%3D%5Csqrt%7BhPKA%7D%5C%20%5CDelta%20T)
We know that area
![A=\dfrac{\pi}{4}d^2](https://tex.z-dn.net/?f=A%3D%5Cdfrac%7B%5Cpi%7D%7B4%7Dd%5E2)
Now when diameter will triples then :
![A_f=\dfrac{\pi}{4}{\left (3d \right )}^2](https://tex.z-dn.net/?f=A_f%3D%5Cdfrac%7B%5Cpi%7D%7B4%7D%7B%5Cleft%20%283d%20%5Cright%20%29%7D%5E2)
![A_f=9A](https://tex.z-dn.net/?f=A_f%3D9A)
![Q'_{fin}=\sqrt{9hPKA}\ \Delta T](https://tex.z-dn.net/?f=Q%27_%7Bfin%7D%3D%5Csqrt%7B9hPKA%7D%5C%20%5CDelta%20T)
![Q'_{fin}=3\sqrt{hPKA}\ \Delta T](https://tex.z-dn.net/?f=Q%27_%7Bfin%7D%3D3%5Csqrt%7BhPKA%7D%5C%20%5CDelta%20T)
![Q'_{fin}=3Q](https://tex.z-dn.net/?f=Q%27_%7Bfin%7D%3D3Q)
So the new heat transfer will increase by 3 times.
Now when copper rod will replace by aluminium rod :
As we know that thermal conductivity(K) of Aluminium is low as compare to Copper .It means that heat transfer will decreases.
Answer:
Check the explanation
Explanation:
beam span = 25 ft
dead load = 0.6 kip/ft
live load = 2.1 kip/ft
factored load = 1.2*0.6 +1.6*2.1=4.08 kip/ft
moment in beam = 4.08*252/8=318.75 kip-ft = 3825 kip-in
design strength =0.9* 50 = 45 ksi
plastic section modulus required = 3825/45=85 in3
Moment in beam in ASD = (0.6+2.1)*252/8 = 210.9 kip-ft
lighest W section from LRFD = W21x44
lightest W section from ASD = W21x44
Answer:
mechanical power used to overcome frictional effects in piping is 2.37 hp
Explanation:
given data
efficient pump = 80%
power input = 20 hp
rate = 1.5 ft³/s
free surface = 80 ft
solution
we use mechanical pumping power delivered to water is
.............1
put here value
= (0.80)(20)
= 16 hp
and
now we get change in the total mechanical energy of water is equal to the change in its potential energy
..............2
and that can be express as
..................3
so
......4
solve it we get
hp
so here
due to frictional effects, mechanical power lost in piping
we get here
put here value
= 16 -13.614
= 2.37 hp
so mechanical power used to overcome frictional effects in piping is 2.37 hp