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Elza [17]
3 years ago
12

a car travels from station A to B at 30kmph during its return trip A it travels 30 km pH for the first half distance and it 70 k

mph for half next half distance find the average speed of the car​
Physics
1 answer:
8_murik_8 [283]3 years ago
3 0

Explanation:

If you cannot visualize it, just assume that the distance from station A to B is 420km. Each half is 210km.

When the car travels from A to B, it takes 420/30 = 14 hours.

When the car travels from B to the halfway point, it takes 210/30 = 7 hours.

When the car travels from the halfway point to A, it takes 210/70 = 3 hours.

Total time taken = 14 + 7 + 3 = 24 hours.

Total distance = 420km * 2 = 840km.

Hence, the average speed of the car is 840/24 = 35km/h.

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2 years ago
When the Glen Canyon hydroelectric power plant in Arizona is running at capacity, 690 m3 of water flows through the dam each sec
igomit [66]

Answer:

The maximum electric power output is P_{max} =1.339*10^{9} \ W

Explanation:

From the question we are told that

        The capacity of the hydroelectric plant is \frac{V}{t}   =  690 \ m^3 /s

         The level at which water is been released is h  =  220 \ m

        The efficiency is  \eta  =0.90

       

The electric power output is mathematically represented as

       P  = \frac{PE_l - PE _o}{t}

Where  PE_l is the potential energy at  level h which is mathematically evaluated as  

          PE_l  =  mgh

and  PE_o  is  the potential energy at ground level which is mathematically evaluated as  

          PE_o  =  mg(0)

         PE_o  =  0

So  

         P  = \frac{mgh}{t}

here  m  =   V *  \rho

where V is volume  and  \rho is density of water whose value is  \rho = 1000 kg/m^3

 So  

         P  = \frac{(\rho * V) * gh}{t}

        P  = \frac{V}{t} * gh \rho

substituting values  

       P  =690 * 9.8 * 220 * 1000

      P  =1.488*10^{9} \ W

The maximum possible electric power output is

           P_{max} = P * \eta

substituting values  

         P_{max} =1.488*10^{9} * 0.90

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6 0
2 years ago
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Answer:

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