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3 years ago

How many atoms are in a 4.7 g copper coin?

Physics

2 answers:

azamat3 years ago

4 0

3.11 is the answer I think

WINSTONCH [101]3 years ago

3 0

Answer:

x = 4.45 * 10 ^22 Note. Technically, this should be rounded to 4.5 * 10^22. There are only 2 sig digits.

Explanation:

You have to assume that the coin is pure copper, which I doubt. What a coin is actually made of depends on when it was minted. But for the sake of this question, we'll assume coins are pure copper.

Copper has an atomic mass of 63.546 grams / mol

So 4.7 g of copper = 4.7 / 63.545 mol

We have 0.07396 mol of copper

1 mol of anything = 6.02 * 10^23 atoms (in this case).

0.07396 mol = x

Cross Multiply

1 * x = 0.07396 * 6.02 * 10^23

x = 4.45 * 10 ^22 atoms of copper

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A 50g ball is released from rest 1.0 above the bottom of thetrack

ludmilkaskok [199]

Answer:

The maximum height of the ball is 2 m.

Explanation:

Given that,

Mass of ball = 50 g

Height = 1.0 m

Angle = 30°

The equation is

$y=\dfrac{1}{4}x^2$

We need to calculate the velocity

Using conservation of energy

$\Delta U_{i}+\Delta K_{i}=\Delta K_{f}+\Delta U_{f}$

Here, ball at rest so initial kinetic energy is zero and at the bottom the potential energy is zero

$\Delta U_{i}=\Delta K_{f}$

Put the value into the formula

$mgh=\dfrac{1}{2}mv^2$

Put the value into the formula

$50\times10^{-3}\times9.8\times1.0=\dfrac{1}{2}\times50\times10^{-3}\times v^2$

$v^2=\dfrac{2\times50\times10^{-3}\times9.8\times1.0}{50\times10^{-3}}$

$v=\sqrt{19.6}$

$v=4.42\ m/s$

We need to calculate the maximum height of the ball

Using again conservation of energy

$\dfrac{1}{2}mv^2=mgh$

Here, h = y highest point

Put the value into the formula

$\dfrac{1}{2}\times50\times10^{-3}\times(4.42)^2=50\times10^{-3}\times9.8\times h$

$y=\dfrac{0.5\times(4.42)^2}{9.8}$

$y=0.996\ m$

Put the value of y in the given equation

$y=\dfrac{1}{4}x^2$

$x^2=4\times0.996$

$x=\sqrt{4\times0.996}$

$x=1.99\ m\ \approx 2 m$

Hence, The maximum height of the ball is 2 m.

4 0

2 years ago

A vertical spring withk= 245N/m oscillates with an amplitude of 19.2cm when 0.457kg hangs from it. The mass posses through the e

Makovka662 [10]

Answer:

y = -19.2 sin (23.15t) cm

Explanation:

The spring mass system is an oscillatory movement that is described by the equation

y = yo cos (wt + φ)

Let's look for the terms of this equation the amplitude I

y₀ = 19.2 cm

Angular velocity is

w = √ (k / m)

w = √ (245 / 0.457

w = 23.15 rad / s

The φ phase is determined for the initial condition t = 0 s , the velocity is negative v (0) = -vo

The speed of the equation is obtained by the derivative with respect to time

v = dy / dt

v = - y₀ w sin (wt + φ)

For t = 0

-vo = -yo w sin φ

The angular and linear velocity are related v = w r

v₀ = w r₀

v₀ = v₀ sinφ

sinφ = 1

φ = sin⁻¹ 1

φ = π / 4 rad

Let's build the equation

y = 19.2 cos (23.15 t + π/ 4)

Let's use the trigonometric ratio π/ 4 = 90º

Cos (a +90) = cos a cos90 - sin a sin sin 90 = 0 - sin a

y = -19.2 sin (23.15t) cm

8 0

3 years ago

Electromagnetic waves require a medium to transfer energy<br> True or False

Simora [160]

The statemengt is <em>false</em>. Electromgnetic waves do not require a medium to transfer energy. They can transfer energy through vacuum (empty space with nothing in it). If electrimagnetic waves needed a medium to move through from place to place, then we could never see the sun, and also it would get very cold here.

7 0

3 years ago

Y=-3x +4 find the domain Nd range

aksik [14]

Is 3678.555667775 correct

3 0

2 years ago

Why is diffraction used in soil profiles?

nekit [7.7K]

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Explanation:

XRD is used to identify the minerals composing clay-rich, hydrothermally altered rocks that occur on several Cascade volcanoes. Such rocks are believed to play an important role in the generation of large landslides and mudflows. XRD is used to analyze saline minerals, including borates.

7 0

2 years ago

How many atoms are in a 4.7 g copper coin?​

How many atoms are in a 4.7 g copper coin?