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3 years ago

5

After walking across a carpeted floor in socks, Jim brings his finger near a metal doorknob and receives a shock. This demonstra

tes that:
Group of answer choices

1 answer:

vovangra [49]3 years ago

6 0

Answer:

After walking across a carpeted floor in socks, Jim brings his finger near a metal doorknob and receives a shock. What does this demonstrate? Frictional forces require direct contact. Electrical forces can act at a distance.

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The initial volume reading in a graduated cylinder is 30 mL. The mass of an irregular shape of an unknown metal piece is 55.3 g.

Vadim26 [7]

Answer:

7.9 $\frac{gr}{cm^3}$

Explanation:

When we put the metal piece in the liquid (which is in the graduated cylinder), how much it goes up is equal to the volume of the piece we inserted.

So now we know that the volume of that piece of unknown metal is 7mL (which is the same as 7 $cm^3$ ).

Density is $\frac{mass}{volume}$ .

So the density of that piece of metal is $\frac{55.3g}{7cm^3}$

Which leaves us with a final density of 7.9 $\frac{gr}{cm^3}$

6 0

3 years ago

A 1.15 kg book is at rest on the table. What is the magnitude of the normal force that the table is exerting on the book?

Agata [3.3K]

Answer:

11.27N

Explanation:

Given parameters:

Mass of the book = 1.15kg

Unknown:

Magnitude of the normal force = ?

Solution:

The normal force is the vertical force exerted by a body on an object.

It can be described as the weight of an object.

Normal force = mass x acceleration due to gravity

Normal force = 1.15 x 9.8 = 11.27N

5 0

2 years ago

Explain the role of energy in changes <br> of state.

slava [35]

A liquid requires enthalpy of vaporization to transform into vapor or gas at its boiling point. Here the element absorbs heat from surroundings or heat source.

This energy is used in breaking the forces of attraction among the atoms and molecules of the element. The molecules get separated to higher distances. The energy is converted in to the kinetic energy of the molecules in gaseous form and into the internal energy in terms of the temperature of the gas.

3 0

3 years ago

How do i turn 36 m/s into mph

gayaneshka [121]

Answer:

me no speak d english

Explanation:

5 0

3 years ago

calculate the diameter of a silver wire of length 75cm , which is extended by 1.85mm when a 10kg mass is suspended from it's end

sdas [7]

Answer: $0.8\ mm$

Explanation:

Given

length of wire $l=75\ cm$

change in length $\Delta l=1.85\ mm$

mass of wire $m=10\ kg$

Young's modulus for silver $E=7.9\times 10^{10}\ N/m^2$

load on wire $F=mg$

$F=10\times 9.8=98\ kg$

change in length is given by

$\Delta l=\dfrac{Pl}{AE}$

Where A=area of cross-section

$A=\dfrac{Pl}{\Delta lE}$

$A=\dfrac{98\times 0.75}{1.85\times 10^{-3}\times 7.9\times 10^{10}}$

$A=\dfrac{73.5}{14.615\times 10^{7}}$

$A=5.029\times 10^{-7}\ m^2$

also wire is the shape of cylinder so cross-section is given by

$A=\dfrac{\pi d^2}{4}=5.029\times 10^{-7}\ m^2$

$\Rightarrow d^2=\dfrac{5.029\times 10^{-7}\times 4}{\pi }$

$\Rightarrow d^2=64.02\times 10^{-8}$

$\Rightarrow d=8\times 10^{-4}\ m$

$\Rightarrow d=0.8\ mm$

4 0

3 years ago