Answer:
a. 51.84Kj
b. 2808.99 W/m^2
c. 11.75%
Explanation:
Amount of heat this resistor dissipates during a 24-hour period
= amount of power dissipated * time
= 0.6 * 24 = 14.4 Watt hour
(Note 3.6Watt hour = 1Kj )
=14.4*3.6 = 51.84Kj
Heat flux = amount of power dissipated/ surface area
surface area = area of the two circular end + area of the curve surface
= 2.136 *10^-4
Heat flux = = 2808.99
fraction of heat dissipated from the top and bottom surface
=11.75%
Answer: See explanation
Explanation:
1. How is diesel fuel ignited in a warm diesel engine?
B. Heat compression
2. Which type of diesel injection produces less noise?
A. Indirect injection (IDI)
3. Which diesel injection system requires the use of a glow plug?
A. Indirect injection (IDI)
4. The three phases of diesel ignition include:
C. Ignition delay, repaid combustion, controlled combustion.
5. What fuel system component is used in a vehicle equipped with a diesel engine that is seldom used on the same vehicle when it is equipped with a gasoline engine?
D. Water-fuel separator
6. The diesel injection pump is usually driven by a _________________.
A. Gear off the camshaft
7. Which diesel system supplies high-pressure diesel fuel to all the injectors all of the time?
C. High-pressure common rail
8. Glow plugs should have high resistance when _____________and lower resistance when __________________.
B. Warm/cold
9. Technician A says that glow plugs are used to help start a diesel engine and are shut off as soon as the engine starts. Technician B says that the glow plugs are turned off as soon as a flame is detected in the combustion chamber. Which Technician is correct?
D. Neither Technicians A NOR B
10. What part should be removed to test cylinder compression on a diesel engine?
D. A glow plug
The correct temperature is 125°C
Answer:
A) M_a1 = 0.5
B) T2 = 232.17 K
C) V2 = 611 m/s
D) m' = 187 kg/s
Explanation:
We are given;
Pressure; P1 = 250 kPa
Temperature; T1 = 125°C = 398 K
Speed; v1 = 200 m/s
Area; A2 = 0.25 m²
M_a2 = 2
A) Formula for M_a1 is given by;
M_a1 = v/a1
Where;
v is speed
a1 = √kRT
k is specific heat capacity ratio of air = 1.4
R is a gas constant with a value of R = 287 J/kg·K
T is temperature
Thus;
M_a1 = 200/√(1.4 × 287 × 398)
M_a1 = 200/399.895
M_a1 = 0.5
B) To find T2, let's first find the Stagnation pressure T0
Thus;
T0/T1 = 1 + ((k - 1)/2) × (M_a1)²
T0 = T1(1 + ((k - 1)/2) × (M_a1)²)
T0 = 398(1 + ((1.4 - 1)/2) × (0.5)²)
T0 = 398(1 + (0.2 × 0.5²))
T0 = 398 × 1.05
T0 = 417.9 K
Now,similarly;
T0/T2 = 1 + ((k - 1)/2) × (M_a2)²
T2 = T0/[(1 + ((k - 1)/2) × (M_a2)²)]
T2 = 417.9/(1 + (0.2 × 2²))
T2 = 417.9/1.8
T2 = 232.17 K
C) V2 is gotten from the formula;
T0 = T2 + (V2)²/(2C_p)
Cp of air = 1005 J/Kg.K
Thus;
V2 = √(2C_p)[T0 - T2]
V2 = √((2 × 1005) × (417.9 - 232.17))
V2 =√373317.3
V2 = 611 m/s
D) mass flow is given by the formula;
m' = ρA2•V2
Where;
ρ is Density of air with an average value of 1.225 kg/m³
m' = 1.225 × 0.25 × 611
m' = 187 kg/s
Answer:
the sun gives off light while at the same time gives off heat. the shoe box cooker takes that heat and light and reflects it around the shoe box. then the heat settles down into whatever is in the shoe box. the heat after being reflected around the shoe box is magnified by the foil wrapped in the box thus allowing the food or drink to be heated. the foil is a conductor of heat because it is metal .
Explanation:
hope this helps!