The following two DC motors are to be compared for certain application:

P9.28 A large vacuum tank, held at 60 kPa absolute, sucks sea- level standard air through a converging nozzle whose throat diame

eimsori [14]

Answer:

a) $m=0.17kg/s$

b) $Ma=0.89$

Explanation:

From the question we are told that:

Pressure $P=60kPa$

Diameter $d=3cm$

Generally at sea level

$T_0=288k\\\\\rho_0=1.225kg/m^3\\\\P_0=101350Pa\\\\r=1.4$

Generally the Power series equation for Mach number is mathematically given by

$\frac{p_0}{p}=(1+\frac{r-1}{2}Ma^2)^{\frac{r}{r-1}}$

$\frac{101350}{60*10^3}=(1+\frac{1.4-1}{2}Ma^2)^{\frac{1.4}{1.4-1}}$

$Ma=0.89$

Therefore

Mass flow rate

$\frac{\rho_0}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}$

$\frac{1.225}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}$

$\rho=0.848kg/m^3$

Generally the equation for Velocity at throat is mathematically given by

$V=Ma(r*T_0\sqrt{T_e}$ )

Where

$T_e=\frac{P_e}{R\rho}\\\\T_e=\frac{60*10^6}{288*0.842\rho}$

$T_e=248$

Therefore

$V=0.89(1.4*288\sqrt{248})\\\\V=284$

Generally the equation for Mass flow rate is mathematically given by

$m=\rho*A*V$

$m=0.84*\frac{\pi}{4}*3*10^{-2}*284$

$m=0.17kg/s$

6 0

2 years ago

What fuel do rockets use

natta225 [31]

Liquid Hydrogen is the fuel used by rockets.

Explanation:

Liquid hydrogen which can be chemically denoted as " $LH_{2}$ " is often considered as the significant fuels for rocket.

However rocket in its lower stages uses fuels such as Kerosene and oxygen where as in the higher stages such as second and third stages it uses liquid hydrogen.

Liquid hydrogen is known to easily cool the nozzle and then also other parts of the rocket before mixing with the oxidizer such as the oxygen.

Thus liquid hydrogen helps in preventing nozzle erosion and also reduces combustion chamber.
Liquid hydrogen one the other hand is very expensive as 384,071 gallons of it will cost approximately $376,389.58 .

Thus liquid hydrogen is effectively used as a fuel for rocket.

8 0

3 years ago

Read 2 more answers

Refers to the capability to keep moving forward on a specified grade.

Mademuasel [1]

Answer:

maneuverability

Explanation:

needless to say, I took the quiz

6 0

2 years ago

A lightweight electric car is powered by ten 12-V batteries. At a speed of 100 km/h, the average frictional force is 1500 N. Wha

Aleksandr [31]

Answer:41.67kW

Explanation: a) power = force * velocity

Convert km/hr to m/s=1000m/(60×60s)

=1000/3600

P=F×vel

Power =1500×100× 1000/3600

=1500×100×5/18

=41,666.67W

=41.67kW

6 0

3 years ago

1. ELECTRICAL SHOCK

lions [1.4K]

Here’s some of them
6. J
7. I
10. O
13. F
14. E
15. N

3 0

3 years ago