Lab: Magnetic and Electric Fields lab report. Edge 2020

A gold sphere of radius R=100 μm and density 19g/cm^3 falls through water. Given the viscosity of water is about 10^-3 Pa s and

icang [17]

The terminal velocity of gold sphere is 39.2 cm/s

<h3>What is terminal velocity?</h3>

Terminal velocity is the maximum velocity attainable for an object as it falls through a fluid.

<h3>How to calculate the terminal velocity of the gold sphere?</h3>

The terminal velocity of the gold sphere is given by v = 2gr²(ρ - σ)/9η where

g = acceleration due to gravity = 9.8 m/s²,
r = radius of sphere = 100 μm = 100 × 10⁻⁶ m = 10⁻⁴ m = 10⁻² cm,
ρ = density of sphere = 19 g/cm³,
σ = density of water = 1.0 g/cm³ and
η = viscosity of water = 10⁻³ Pa-s

So, susbtituting the values of the variables into the equation, we have that

v = 2gr²(ρ - σ)/9η

v = 2 × 9.8m/s²× (10⁻² cm)²(19 g/cm³ - 1.0 g/cm³)/(9 × 10⁻³ Pa-s)

v = 2 × 9.8 m/s² × 10⁻⁴ cm² × (18 g/cm³)/(9 × 10⁻³ Pa-s)

v = 2 × 980 cm/s² × 10⁻⁴ cm² × 2 g/cm³/(1 × 10⁻³ Pa-s)

v = 3920 g/s² × 10⁻⁴/(1 × 10⁻³ Pa-s)

v = 392 cm/s × 10³ × 10⁻⁴

v = 392 × 10⁻¹ cm/s

v = 39.2 cm/s

So, the terminal velocity is 39.2 cm/s

Learn more about terminal velocity of sphere here:

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4 0

1 year ago

A heavy solid disk rotating freely and slowed only by friction applied at its outer edge takes 120 seconds to come to a stop.

alisha [4.7K]

Answer:

The time is 16 min.

Explanation:

Given that,

Time = 120 sec

We need to calculate the moment of inertia

Using formula of moment of inertia

$I=\dfrac{1}{2}MR^2$

If the disk had twice the radius and twice the mass

The new moment of inertia

$I'=\dfrac{1}{2}\times2M\times(2R)^2$

$I'=8I$

We know,

The torque is

$\tau=F\times R$

We need to calculate the initial rotation acceleration

Using formula of acceleration

$\alpha=\dfrac{\tau}{I}$

Put the value in to the formula

$\alpha=\dfrac{F\times R}{\dfrac{1}{2}MR^2}$

$\alpha=\dfrac{2F}{MR}$

We need to calculate the new rotation acceleration

Using formula of acceleration

$\alpha'=\dfrac{\tau}{I'}$

Put the value in to the formula

$\alpha=\dfrac{F\times R}{8\times\dfrac{1}{2}MR^2}$

$\alpha=\dfrac{2F}{8MR}$

$\alpha=\dfrac{\alpha}{8}$

Rotation speed is same.

We need to calculate the time

Using formula angular velocity

$\Omega=\omega'$

$\alpha\time t=\alpha'\times t'$

Put the value into the formula

$\alpha\times120=\dfrac{\alpha}{8}\times t'$

$t'=960\ sec$

$t'=16\ min$

Hence, The time is 16 min.

5 0

3 years ago

Molly is looking for a sustainable fuel source that doesn't require technical equipment to harness. She is concerned that trees

notka56 [123]

Answer:

She can consider using agricultural waste or dried dung.

Explanation:

No doubt, biomass has become a crucial source of energy to the society, with almost 90% of the households in rural area now relying on biomass for energy. Biomass has become a great option for household heating and cooking. It is locally available and abundant. It is a clean type of fuel, unlike fossil fuels and it somehow helps in cleaning our environment as it traps carbondioxide. Some common types of biomass include dried dung, agricultural waste, or even charcoal.

8 0

3 years ago

Read 2 more answers

According to Newton's first law, if an object is changing direction, what must be happening?

murzikaleks [220]

D. Unbalanced forces are acting on it.

hope this helped

6 0

3 years ago

A block of inertia m is placed on an inclined plane that makes an angle θ with the horizontal. The block is given a shove direct

Wittaler [7]

Answer:

A) d = v² / (2g (μ cos θ + syn θ) B) μ = tan θ

Explanation:

Part A

We can work this part with the work and energy theorem, where the work of the friction forces is equal to the energy change of the system.

The work is

W = fr .d

With the force of friction it opposes the movement

W = - fr d

The energy at the lowest point is

Em₀ = K = ½ m v²

The energy at the highest point

$Em_{f}$ = U = m g y

The height (y) can be found by trigonometry

sin θ = y / d

y = d sin θ

W = $Em_{f}$ –Em₀

-fr d = mg d sin θ - ½ m v²

The equation for the force of friction is

fr = μ N

From Newton's second law

N - W cos Te = 0

We replace

-μ (mg cos θ) d - mg d sin θ = - ½ m v²

d g (μ cos θ + sin θ) = ½ v²

d = v² / (2g (μ cos θ + syn θ)

Part B

The block is stopped, what is the Angle tet, let's use Newton's second law

fr - W sin θ = 0 ⇒ fr = W sin θ

N - W cos θ= 0 ⇒ N = w cos θ

fr = μ N

μ (mg cos θ) = mg syn θ

μ = syn θ / cos θ

μ = tan θ

7 0

3 years ago