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s2008m [1.1K]
3 years ago
5

A car moves at a speed of 40 miles per hour for half an hour and then at 60 miles per hour for two hours. What is the average sp

eed, measured in miles per hour, for the entire trip?
Physics
1 answer:
katovenus [111]3 years ago
7 0

Answer:

The average speed for the entire trip is 56 miles/hour.

Explanation:

It is given that,

Initially, the car moves with a speed of, v₁ = 40 miles/hour

Initial time, t₁ = 0.5 hours

Distance covered during time t₁,

d_1=v_1t_1

d_1=40\times 0.5

d_1=20\ miles

Then it travels with a speed of, v₂ = 60 miles/hour

Then time taken, t₂ = 2 hours

Distance covered during time t₂,

d_2=v_2t_2

d_2=60\times 2

d_2=120\ miles

The average speed of the car can be calculated as :

v=\dfrac{d_1+d_2}{t_1+t_2}

v=\dfrac{120+20}{0.5+2}

v = 56 miles/hour

So, the average speed of the car for the entire trip is 56 miles/hour. Hence, this is the required solution.  

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Answer:

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2 years ago
Potassium is a crucial element for the healthy operation of the human
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Answer:

1

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2

  The Dose per year in Sieverts is   Dose_s = 26.4 *10^{-10}

Explanation:

From the question we are told that

   The isotopes of potassium in the body are Potassium-39, Potassium-40, and Potassium- 41

    Their abundance is 93.26%, 0.012% and 6.728%

   The mass of potassium contained in human body is  m = 3.0 g = \frac{3}{1000} = 0.0003 \ kg per kg of the body

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Now the mass of  potassium  in this body is mathematically evaluated as

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substituting value

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The Dose in Sieverts is evaluated as

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       Dose_s = 1.2 * 22*10^{-10}

       Dose_s = 26.4 *10^{-10}

             

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Answer:

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