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Murljashka [212]

4 years ago

12

After three times the particle half-life of radioactive particle, 1/4 of the particle will remain un-decayed. O True O False

1 answer:

Roman55 [17]4 years ago

6 0

Answer:

False

Explanation:

Let the initial amount is No.

Let t be the half life.

Half life is the time in which the initial amount of the substance becomes half and the remaining amount in teh sample is also half.

After one half life, the remaining amount is No / 2

After two half lives, the remaining amount is No / 4

After three half lives, the remaining amount is No / 8.

So, the statement is false.

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To illustrate the use of a multistage rocket consider the following:

garri49 [273]

Answer:

a

$v_f = 0.916 v_{ex}$

b

$v_f = 1.05 v_{ex}$

Explanation:

Considering question a

From the question we are told that

The mass of the rocket is $m_o$

The mass of the fuel which is in the rocket is m = 0.6 M

Generally given that the rocket burns all it fuel in a single stage , the final velocity of the rocket is mathematically represented as

$v_f = v_{ex} ln [\frac{m_o}{m_k} ]$

Here $m_k$ is the mass of the rocket without fuel which is mathematically evaluated as

$m_k = m_o- m$

=> $m_k = m_o -0.6m_o$

=> $m_k = [1- 0.6] m_o$

=> $v_f = v_{ex} ln [\frac{m_o}{[1 - 0.6]m_o} ]$

=> $v_f = 0.916 v_{ex}$

Considering question b

From the question we are told that

The mass of the fuel it burn at the first stage is $m = 0.3 m_o$

The mass of the first stage fuel tank $m_1 = 0.1 m_o$

The mass of the fuel at the second stage is $m_f = 0.3m_o$

Generally the velocity of the rocket at the first stage is mathematically represented as

$v_i = v_{ex} * ln [ \frac{m_o }{[1- m]m_o } ]$

=> $v_i = v_{ex} * ln [ \frac{m_o }{[1- 0.3]m_o } ]$

=> $v_i = v_{ex} * ln [ \frac{1 }{0.7 } ]$

=> $v_i =0.357 v_{ex}$

Generally the mass of the rocket after first stage is

$m_r = m_o - 0.3m_o -0.1m_o$

=> $m_r = 0.6m_o$

Generally the final velocity of the rocket at the second stage is

$v_f = v_i + v_{ex} * ln [\frac{m_r}{ m_f } ]$

=> $v_f = v_i + v_{ex} * ln [\frac{0.6 m_o }{0.3mo } ]$

=> $v_f = 0.357 v_{ex} + 0.693 v_{ex}$

=> $v_f = 1.05 v_{ex}$

4 0

3 years ago

Why are surface salinities higher than deepwater salinities in the tropics?

muminat

Surface salinities are higher than deepwater salinities because of the high amount of rainfall that tends to dilute the water on the surface. Higher salinities are observed to take place at "<span>about 36.7 ppt near 30° North and South" where these locations have little to no precipitation. </span>

4 0

4 years ago

What is the answer to this problem?

djyliett [7]

Answer:

The answer is A

Explanation:

An insulator doesn't have to be a metal

3 0

3 years ago

Read 2 more answers

physics major is cooking breakfast when he notices that the frictional force between the steel spatula and the Dry Steel frying

givi [52]

Answer:0.667 N

Explanation:

Given

It is noticed that Frictional Force is 0.2 N

Coefficient of kinetic Friction $\mu _k=0.3$

We know Friction Force is given by

$f_r=\mu _k\times Normal\ reaction$

therefore

$0.2=\mu _k\times N$

$0.2=0.3\cdot N$

$N=\frac{0.2}{0.3}$

$N=0.667 N$

8 0

3 years ago

What is the mass of a 4900 n bobsled?

hammer [34]

The mass of a 4,900 newtons bobsled is 500 kilograms.

8 0

3 years ago