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3 years ago

An elements atomic number is 85 how many protons would an atom of this element have?

Physics

2 answers:

garik1379 [7]3 years ago

5 0

85 protons are in astatine have.

ArbitrLikvidat [17]3 years ago

3 0

The atomic number and number of protons is the same thing :)

So here, your atom would have 85 protons.

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Help quick<br> p;leaseeeeeeeeeeee its about direction and magnitude

KonstantinChe [14]

Explanation:

The net force of each square is the combination of the forces in each direction. The direction is the... direction the square would go in due to the net force. The magnitude of the net force is how large it is. So if you had a force pushing 2N to the left and 1N to the right, then the net force would be 1N to the left; because the two oppose eachother. If they were going in the same direction, then they'd add to each other. And perpendicular net forces (like one pushing up and another pushing left) can create net forces in diagonal directions.

I'm not going to do all of these for you because they're basically all the same thing and it's good practice for you anyway. But I'll do the first three just so you can get the idea:

1. The net force's magnitude is 4N and it's direction is to the right.

2. The net force's magnitude is 4N and it's direction is to the left.

3. The net force's magnitude is 0N and it has no direction because they are equal forces acting in opposite directions.

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3 years ago

When designing an experiment, why is it important to test only one variable?

m_a_m_a [10]

That's the only way you can get consistent and accurate results.

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3 years ago

Read 2 more answers

Lagrangian mechanics. Determine the equations of motion for a particle of mass m constrained to move on the surface of a cone in

maria [59]

Answer:

Explanation:

Hi!

In order to obtain the Lagrangian of the system we must first write the Kinetic and Potential Energies. Lets orient our axes such that the axis of the cone coincide with the z axis. In cilindrical coordinates we have

$v^{2} = \frac{dr}{dt}^{2} +r^{2} \frac{d\theta }{dt} ^{2} +\frac{dz}{dt} ^{2}$ - (1)

But, since the particle is constrained to move on the surface of the cilinder, we have the following relation between r and z:

$\frac{r}{z}=tan(45)$

or:

$z = r cot(45)$ - (2)

and:

$\frac{dz}{dt} = \frac{dr}{dt} cot(45)$

replacing (2) in (1) we obtain:

$v^{2} = \frac{dr}{dt}^{2} (1+cot(45))+r^{2}\frac{d\theta }{dt} ^{2}$ - (3)

Now the kinetic energy is given as:

$T = \frac{1}{2}m(\frac{dr}{dt}^{2} (1+cot(45))+r^{2}\frac{d\theta }{dt} ^{2})$ - (4)

And the potential energy is given by:

$V = -mgz = -mgr cot(45)$

So the Langrangian is given by:

$L = T - V= \frac{1}{2}m(\frac{dr}{dt}^{2}(1+cot(45)+r^{2})\frac{d\theta }{dt} ^{2}) + mgr cot(45)$

And the equations of motion are:

For θ

$\frac{d}{dt} (mr\frac{d\theta}{dt}) = 0-->mr{d\theta}{dt}=c$

For r

$\frac{d}{dt}(m\frac{dr}{dt}(1+cot(45) )= mgcot(45)+mr\frac{d\theta}{dt} ^{2}\\m\frac{d^{2} r}{dt^{2} }(1+cot(45)= mgcot(45)+mr\frac{d\theta}{dt} ^{2}$

Obtained from the Euler-Langrange equations

Here the conserved quantity is given by the first equation of motion, namely:

$mr\frac{d\theta}{dt}=c$

Which is the magnitude of the angular momentum

7 0

3 years ago

What are three basic parts that make up all atoms?

uysha [10]

Three parts that make up atoms?
1;protons
2;neutrons
3;Electrons

6 0

3 years ago

If a ray incidents normally on a plane mirror,what will be the angle of reflection?

olga nikolaevna [1]

Explanation:

The Second Law of Reflection states that the angle of incidence is always equal to the angle of reflection. Therefore, the angle of reflection is same as the angle of incidence, that is, 00. So, the reflected ray will retrace the path of the incident ray.

6 0

2 years ago