<span>4) Formation of a gas
When methane burns, it produces the gases water vapor and carbon dioxide.
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B. only its velocity should change
Given:
Area of pool = 3m×4m
Diameter of orifice = 0.076m
Outlet Velocity = 6.3m/s
Accumulation velocity = 1.5cm/min
Required:
Inlet flowrate
Solution:
The problem can be solved by this general formula.
Accumulation = Inlet flowrate - Outlet flowrate
Accumulation velocity × Area of pool = Inlet flowrate - Outlet velocity × Area of orifice
First, we need to convert the units of the accumulation velocity into m/s to be consistent.
Accumulation velocity = 1.5cm/min × (1min/60s)×(1m/100cm)
Accumulation velocity = 0.00025 m/s
We then calculate the area of the pool and the area of the orifice by:
Area of pool = 3 × 4 m²
Area of pool = 12m²
Area of orifice = πd²/4 = π(0.076m)²/4
Area of orifice = 0.00454m²
Since we have all we need, we plug in the values to the general equation earlier
Accumulation velocity × Area of pool = Inlet flowrate - Outlet velocity × Area of orifice
0.00025 m/s × 12m² = Inlet flowrate - 6.3m/s × 0.00454m²
Transposing terms,
Inlet flowrate = 0.316 m³/s
Answer:
(a) 1320 W
(b) 480 W
(c) E':E ≈ 11:2
Explanation:
(a) Applying,
P' = VI'................. Equation 1
Where P' = Power of the blow-dryer, V = Voltage, I = current rating of the blow-dryer.
From the question,
Given: V = 120 V, I' = 11 A
Substitute these values into equation 1
P = (120×11)
P = 1320 W
(b) Similarly,
P = VI................... Equation 2
Where P = Power of the vacuum cleaner. I = current rating of the vacuum cleaner.
Also Given: I = 4 A,
Therefore
P = 4(120)
P = 480 W
(c)
E' = P'/t'............. Equation 3
E = P/t................ Equation 4
Where E' = Energy of the blow-dryer, t' = time of use of the blow-dryer, E = Energy of the vacuum cleaner, t = time of use of the vacuum cleaner
From the question,
Given: t' = 15 minutes = (15×60) = 900 seconds, t = 30 minutes = (30×60) = 1800 seconds
Substitute these values into equation 3 and 4
E' = 1320/900
E' = 1.47 J,
E = 480/1800
E = 0.267
Therefore,
E':E = 1.47:0.267
E':E ≈ 11:2
