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3 years ago

In which of these cases do we have enough information to say that the atom is electrically neutral?

2 answers:

5 0

<span>So we want to know when do we have enough information about the atom that we can say that it is electrically neutral. So the information we need to know is the number of protons, whic are positively charged particles and the number of electrons which are negatively charged particles. Number of protons has to be equal to number of electrons for the atom to have neutral charge. Neutrons are electrically neutral so their number doesn't change the charge of the atom. So the correct answer is B. </span>

Svetradugi [14.3K]3 years ago

3 0

B. 7 protons and 7 electrons, just took the test

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In photography what are clouds best described as?

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4 years ago

Which characterstics do venus and earth share

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Answer:

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3 years ago

Explain why a ball thrown in space could keep moving forever, while a ball thrown here on Earth will come to a stop.

Dmitriy789 [7]

Answer:

In space there is no air resistance. on earth there is

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3 years ago

The tides on earth are caused mainly by earths gravitational interactions with which of the following?

Llana [10]

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3 years ago

Suppose that a wind is blowing in the direction S45°E at a speed of 30 km/h. A pilot is steering a plane in the direction N60°E

Kay [80]

Answer:

The true course: $40.29^\circ$ north of east

The ground speed of the plane: 96.68 m/s

Explanation:

Given:

$V_w$ = velocity of wind = $30\ km/h\ S45^\circ E = (30\cos 45^\circ\ \hat{i}-30\sin 45^\circ\ \hat{j})\ km/h = (21.21\ \hat{i}-21.21\ \hat{j})\ km/h$

$V_p$ = velocity of plane in still air = $100\ km/h\ N60^\circ E = (100\cos 60^\circ\ \hat{i}+100\sin 60^\circ\ \hat{j})\ km/h = (50\ \hat{i}+86.60\ \hat{j})\ km/h$

Assume:

$V_r$ = resultant velocity of the plane

$\theta$ = direction of the plane with the east

Since the resultant is the vector addition of all the vectors. So, the resultant velocity of the plane will be the vector sum of the wind velocity and the plane velocity in still air.

$\therefore V_r = V_p+V_w\\\Rightarrow V_r = (50\ \hat{i}+86.60\ \hat{j})\ km/h+(21.21\ \hat{i}-21.21\ \hat{j})\ km/h\\\Rightarrow V_r = (71.21\ \hat{i}+65.39\ \hat{j})\ km/h$

Let us find the direction of this resultant velocity with respect to east direction:

$\theta = \tan^{-1}(\dfrac{65.39}{71.21})\\\Rightarrow \theta = 40.29^\circ$

This means the the true course of the plane is in the direction of $40.29^\circ$ north of east.

The ground speed will be the magnitude of the resultant velocity of the plane.

$\therefore Magnitude = \sqrt{71.21^2+65.39^2} = 96.68\ km/h$

Hence, the ground speed of the plane is 96.68 km/h.

5 0

3 years ago