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hichkok12 [17]
3 years ago
11

A carbon rod with a radius of 2.1 mm is used to make a resistor. The resistivity of this material is 3.2 × 10−5 Ω · m. What leng

th of the carbon rod should be used to make a 13.7 Ω resistor?
Physics
1 answer:
Eduardwww [97]3 years ago
5 0

Answer:

5.93 m

Explanation:

The carbon rod has a radius of 2.1 mm; it can be converted to meter by

1 m = 1000 mm

1 m ÷1000 = 1 mm

2.1 mm = 2.1 × 1 mm = 2.1 ×1÷1000 m = 0.0021 m

using the formula for resistance of a wire

R = ρl÷A, where R is the resistance of the carbon rod in ohms, ρ is resistivity in ohms.m, l is the length of the rod and A is the cross sectional area in m².

A = π r²

Make l the subject of the formula by cross multiplying

RA = ρl

divide both side by ρ

RA÷ρ = ρl÷ρ

RA÷ρ = l

substitute the values in

13.7 × 0.0021 × 0.0021 × 3.142 ÷ 3.2 × 10^-5 = 5.93 m

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Two conducting spheres of different sizes are at the same potential. The radius of the larger sphere is four times larger than t
Sergeeva-Olga [200]

Answer:

0.8

Explanation:

The two spheres have the same potential, V.

Let the radius of the larger sphere be R and the radius of the smaller sphere be r,

=> R = 4r

Let the charge on the smaller sphere be q. Hence, the larger sphere will have charge Q - q.

The potential of the smaller sphere will be:

V_S = \frac{kq}{r}

The potential of the larger sphere will be:

V_L = \frac{k(Q - q)}{R}

Inputting R = 4r,

V_L = \frac{k(Q - q)}{4r}

Since V_S = V_L = V,

\frac{k(Q - q)}{4r} = \frac{kq}{r}

=> Q - q = 4q

=> 5q = Q

q = 0.2Q

The fraction of the charge Q that rests on the smaller sphere is 0.2

The charge of the larger sphere is:

Q - q = Q - 0.2Q = 0.8Q

∴ The fraction of the total charge Q that rests on the larger sphere is 0.8

7 0
3 years ago
How many board feet of lumber are needed assuming 200 lin. Ft. of 2""x 6"" lumber a. 12 b. 16.67 c. 120 d. 200
Svetach [21]

Answer:

B) 16.67

Explanation:

If the dimension of one lumber is 2" × 6", the total area of one lumber will be 12inch²

If the total board feet of lumber there is 200in, therefore the total board of lumber that will be needed is 200/12 which gives 16.67 lumbers

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How does a mathematical model help you understand the science concepts
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It can help with measurements and when you want to add measurements to a cylinder or a beaker so ya
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3 years ago
DEFINE the term free fall
PtichkaEL [24]

Answer:

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Explanation:

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3 years ago
Read 2 more answers
1. When you have different masses for each sphere, how does the force that the larger mass sphere exerts on the smaller mass sph
aleksandrvk [35]

1) The forces are equal (Newton's third law of motion)

2) The force between the spheres will quadruple

3) The force of gravity exerted by the notebook on you is negligible

Explanation:

1)

In this part of the problem, we want to compare the gravitational force exerted by the larger mass sphere on the smaller mass sphere to the force exerted by the smaller mass sphere to the larger mass sphere.

We can do this by using Newton's third law of motion, which states that:

<em>"When an object A exerts a force (called </em><em>action</em><em>) on an object B, then object B exerts an equal and opposite force (called </em><em>reaction</em><em>) on object A"</em>

In this problem, we can identify the larger mass sphere as object A and the smaller mass sphere as object B. This law tells us that the two forces are equal in magnitude and opposite in direction: therefore, the gravitational force exerted by the larger mass sphere on the smaller mass sphere is equal to the force exerted by the smaller mass sphere to the larger mass sphere.

2)

The magnitude of the gravitational force between the two spheres is given by

F=G\frac{m_1 m_2}{r^2}

where

G is the gravitational constant

m_1, m_2 are the masses of the two spheres

r is the separation between the two spheres

In this problem, we are asked to find what happens when the distance between the spheres is halved, therefore when the new distance is

r'=\frac{r}{2}

Substituting into the equation, we find

F'=G\frac{m_1 m_2}{r'^2}=G\frac{m_1 m_2}{(r/2)^2}=4(\frac{Gm_1 m_2}{r^2})=4F

So, the force between the two spheres will quadruple.

3)

We can give an estimate for the gravitational force exerted by your notebook on you.

As we said, the magnitude of the gravitational force is

F=G\frac{m_1 m_2}{r^2}

Where:

G=6.67\cdot 10^{-11} m^3 kg^{-1}s^{-2} is the gravitational constant

Let's estimate the following:

m_1 = 60 kg is your mass

m_2 = 2 kg is the mass of the notebook

r=1 m, assuming the notebook is at 1 metre from you

Substituting,

F=(6.67\cdot 10^{-11})\frac{(60)(2)}{1^2}=8.0\cdot 10^{-9} N

We see that this force has an extremely small value: therefore, it is almost negligible in daily life, where other much stronger forces act on you.

Learn more about gravity:

brainly.com/question/1724648

brainly.com/question/12785992

#LearnwithBrainly

8 0
3 years ago
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