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4 years ago

What will the surface charge density be if the radius of the disk is doubled but its total charge remains the same

Physics

1 answer:

zaharov [31]4 years ago

8 0

Answer:

the new surface charge density = Q/4πr²( initial surface charge density divided by 4)

Explanation:

charge density(surface) = Q/A = charge/area

let r be the initial radius of the disk

therefore, area A = πr²

charge density = Q/πr²

Now that the radius is doubled, let it be represented as R

∴ R = 2r

Recall, charge density = Q/A

A = πR = π(2r)² = 4πr²

the new surface charge density = Q/4πr²

the initial surface charge density divided by 4

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An object located near the surface of Earth has a weight of a 245 N

marusya05 [52]

Answer:

The mass of the object is 24.5 kg and weight of the object on Mars is 91.14 N.

Explanation:

Weight of the object on the surface of Earth, W = 245 N

On the surface of Earth, acceleration due to gravity, g = 10 m/s²

Weight of an object is given by :

W = mg

m is mass

$m=\dfrac{W}{g}\\\\m=\dfrac{245\ N}{10\ m/s^2}\\\\=24.5\ kg$

So, the mass of the object is 24.5 kg

Acceleration due to gravity on Mars, g' = 3.72 m/s²

Weight of the object on Mars,

W' =mg'

W' = 24.5 kg × 3.72 m/s²

= 91.14 N

So, the weight of the object on Mars is 91.14 N.

4 0

3 years ago

An ion source is producing 6Li ions, which have charge +e and mass 9.99 × 10-27 kg. The ions are accelerated by a potential diff

Mkey [24]

Answer:

$5.38\cdot 10^5 V/m$

Explanation:

At first, the 6Li ions are accelerated by the potential difference, so their gain in kinetic energy is equal to the change in electric potential energy; so we can write:

$q\Delta V=\frac{1}{2}mv^2$

where

$q=+e=+1.6\cdot 10^{-19}C$ is the charge of one 6Li ion

$\Delta V=9.2 kV=9200 V$ is the potential difference through which they are accelerated

$m=9.99\cdot 10^{-27}kg$ is the mass of each ion

v is the final speed reached by the ions

Solving for v, we find:

$v=\sqrt{\frac{2q\Delta V}{m}}=\sqrt{\frac{2(1.6\cdot 10^{-19})(9200)}{9.99\cdot 10^{-27}}}=5.43\cdot 10^5 m/s$

After that, the ions pass into a region with a uniform magnetic field of strength

$B=0.99 T$

The magnetic field exerts a force perpendicular to the direction of motion of the ions, and this force is given by

$F=qvB$

In order to make the ions passing through undeflected, there should be an electric force balancing this magnetic force. The electric force is given by

$F=qE$

where E is the strength of the electric field.

Since the two forces must be balanced,

$qE=qvB$

From which we get

$E=vB$

So the strength of the electric field must be

$E=(5.43\cdot 10^5)(0.99)=5.38\cdot 10^5 V/m$

4 0

3 years ago

I have 15 minutes left to answer someone pls help, thank you very much.

Ira Lisetskai [31]

Your answer is a)
Happy to assist you!

8 0

3 years ago

What is the ﬁnal equilibrium temperature when 12 g of milk at 7◦C is added to 175 g of coﬀee at 69◦C? Assume the speciﬁc heats o

lina2011 [118]

Answer:

ﬁnal equilibrium temperature is 65.02 ◦C

Explanation:

Given data

milk = 12 g

temp milk = 7◦C

coffee = 175 g

coffee temp = 69◦C

to find out

ﬁnal equilibrium temperature

solution

we apply here equilibrium condition i.e m c ΔT

milk mass × c × ΔT = coffee mass × c × ΔT

12 × 1 × (T- 7) = 175 × 1 × ( 69- T)

12T - 84 = 12075 - 175 T

187 T = 12159

T = 65.02

so ﬁnal equilibrium temperature is 65.02 ◦C

3 0

4 years ago

Which botany phenomenon is primarily based on an understanding of physics

erik [133]

The botany phenomenon that is primarily based on an understanding of physics is t<span>he way plant pollen is carried by wind to another plant. It has to do with motion and acceleration, which are all the things that physics studies. </span>

3 0

4 years ago

Read 2 more answers