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2 years ago

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car was moving in a straight road of length 320 km it covered 240 km with an average velocity 75 km/hr then it ran out of fuel a

nd stopped for 0.6 hr until it was refueled and completed its journey with a velocity 100 km/hr so the average velocity during the whole journey

1 answer:

Stella [2.4K]2 years ago

6 0

The average velocity of the car for the whole journey is 69.57 km/h.

The given parameters:

<em>Length of the road, L = 320 km</em>
<em>Distance covered = 240 km at 75 km/h</em>
<em>time spent refueling, t₂ = 0.6 hr</em>
<em>Final velocity, = 100 km/hr</em>

The time spent by the before refueling is calculated as follows;

$t = \frac{d}{v} \\\\t_1 = \frac{240}{75} \\\\t_1 = 3.2 \ hours$

The time spent by the car for the remaining journey;

$t_3 = \frac{320 - 240}{100} \\\\t_3 = 0.8 \ hr$

The total time of the journey is calculated as follows;

$t = t_1 + t_2 + t_3\\\\t = 3.2 \ hr \ + \ 0.6 \ hr \ + \ 0.8 \ hr\\\\t = 4.6 \ hours$

The average velocity of the car for the whole journey is calculated as follows;

$v = \frac{total \ distance }{total \ time} \\\\v = \frac{320}{4.6} \\\\v = 69.57 \ km/h$

Learn more about average velocity here: brainly.com/question/6504879

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2 years ago

Suppose that the half-life of an element is 1000 years. How many half-lives will it take before one-eighth of the original sampl

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The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.

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A 40-kg rock is dropped from an elevation of 10 m. What is the velocity of the rock when it is 5-m from the ground?

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Answer:

Explanation:

Given

mass of rock $m=40\ kg$

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2 years ago

Cesium-137 undergoes beta decay and has a half-life of 30.0 years. How many beta particles are emitted by a 14.0-g sample of ces

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Answer: $0.81\times 10^{16}$ beta particles

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Where $N_t$ =atoms left undecayed

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The fraction that decays : $1-(\frac{1}{2})^{\frac{3}{1.577\times 10^7}}=1.32\times 10^{-7}$

Amount of particles that decay is = $0.614\times 10^{23}\times 1.32\times 10^{-7}=0.81\times 10^{16}$

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