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2 years ago

Which of the following conditions were present in over 80% of paddling fatalities from 1995-2000?

Engineering

1 answer:

Minchanka [31]2 years ago

3 0

Answer:

80% of the people that were killed weren't wearing a safety flotation device ( in correct terminology Personal Flotation Device, or PFD )

Explanation:

Hence they drowned due to the lack of safety.

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A waste stabilization pond is used to treat a dilute municipal wastewater before the liquid is discharged into a river. The infl

german

Answer:

BOD concentration at the outflow = 17.83 mg/L

Explanation:

given data

flow rate of Q = 4,000 m³/day

BOD1 concentration of Cin = 25 mg/L

volume of the pond = 20,000 m³

first-order rate constant equal = 0.25/day

to find out

What is the BOD concentration at the outflow of the pond

solution

first we find the detention time that is

detention time t = $\frac{volume}{flow rate}$

detention time t = $\frac{20000}{4000}$

detention time = 5 days

BOD concentration at the outflow of pond is express as

BOD concentration at the outflow = $Cin ( 1 - e^{-kt} )$

here k is first-order rate constant and t is detention time and Cin is BOD1 concentration

BOD concentration at the outflow = $25 ( 1 - e^{-0.25(5)} )$

BOD concentration at the outflow = 17.83 mg/L

8 0

3 years ago

A rigid, well-insulated tank of volume 0.9 m is initially evacuated. At time t = 0, air from the surroundings at 1 bar, 27°C beg

Eva8 [605]

Answer:

$\dot{w}$ = -0.303 KW

Explanation:

This is the case of unsteady flow process because properties are changing with time.

From first law of thermodynamics for unsteady flow process

$\dfrac{dU}{dt}=\dot{m_i}h_i+\dot{Q}-\dot{m_e}h_i+\dot{w}$

Given that tank is insulated so $\dot{Q}=0$ and no mass is leaving so

$\dot{m_e}=0$

$\int dU=\int \dot{m_i}h_i\ dt-\int \dot{w}\ dt$

$m_2u_2-m_1u_1=(m_2-m_1)h_i- \dot{w}\Delta t$

Mass conservation $m_2-m_1=m_e-m_i$

$m_1,m_2$ is the initial and final mass in the system respectively.

Initially tank is evacuated so $m_1=0$

We know that for air $u=C_vT ,h=C_p T$ , $P_2v_2=m_2RT_2$

$m_2=0.42 kg$

So now putting values

$0.42 \times 0.71 \times 730=0.42\times 1.005\times 300- \dot{w} \times 300$

$\dot{w}$ = -0.303 KW

3 0

3 years ago

What is engineering?

ANTONII [103]

Answer:

the branch of science and technology concerned with the design, building, and use of engines, machines, and structures. Anything that involves engines, wires, etc. basically

8 0

2 years ago

If using the washer results in the wheel brake units getting wet, ensure that the vehicle is driven for a short distance with th

Elden [556K]

Answer:

whats the question

Explanation:

6 0

2 years ago

Read 2 more answers

Apply it

Kipish [7]

To indentify the machines in our school that have a pulley system as the drive mechanism and the advantages of Pulley system is given below

Explanation:

1.A pulley is a wheel with a groove along its edge, that holds a rope or cable. ... When pulleys are used together in this way, they reduce the amount of force needed to lift a load. A crane uses pulleys to help it lift heavy loads. Pulleys are one of the six simple machines.

2.Examples of pulleys include:

Elevators use multiple pulleys in order to function.
A cargo lift system that allows for items to be hoisted to higher floors is a pulley system.
Wells use the pulley system to hoist the bucket out of the well.
Many types of exercise equipment use pulleys in order to function.

3.Using multiple pulleys decreases the amount of force necessary to move an object by increasing the amount of rope used to raise the object. The mechanical advantage (MA) of a pulley system is equal to the number of ropes supporting the movable load.

4.To calculate the mechanical advantage of a pulley you simply have to count the number of rope sections that support whatever object you are lifting (not counting the rope that is attached to the effort). For example, in a one pulley system the MA is 1. ... Therefore your mechanical advantage would be 2 (600/300).

5.The movable pulley is used to reduce the amount of input force to lift a load. The most popular system that uses this pulley would be a well. Unlike the fixed pulley, the movable pulley is attached to the load, and is lifted by pulling up on the rope, making it twice as easier to lift a heavy object.

6.The main benefit of the pulley is that it can actually reduce the amount of force which is required to lift heavy objects and redistributes the direction of the force to lift heavy objects

7 0

2 years ago