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4 years ago

The bohr model of the atom addressed the problem of

1 answer:

7 0

Rutherford's nuclear model stated that a cloud of negative electrons surround the nucleus however scientists realized that electrons in a cloud around the nucleus of an atom would be attracted to the nucleus, causing the atom to collapse. Thus Bohr's model proposed that electrons were contained in shells and they orbit the nucleus at fixed distances.

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Why can making observations be a very good way to come up with a scientific question?

astra-53 [7]

Because observation is a guess that you make and study on that certain topic.

5 0

3 years ago

A student solving a physics problem to find the unknown has applied physics principles and obtained the expression: μkmgcosθ=mgs

AlladinOne [14]

Solution :

Given expression :

$\mu_k$ mgcosθ = mgsinθ − ma

Here, g = 9.8 $m/s^2$ , a = 3.60 $m/s^2$ , θ = 27°

Therefore,

$\mu_k mg \cos \theta = mg \sin \theta - ma$

$\mu_k mg \cos \theta = m(g \sin \theta - a)$

$\mu_k g \cos \theta = (g \sin \theta - a)$

$\mu_k =\frac{(g \sin \theta-a)}{g \cos \theta}$

Mow calculating the coefficient of kinetic friction as follows :

$\mu_k=\frac{g \sin \theta-a}{g \cos \theta}$

$\mu_k=\frac{9.8 \times \sin 27^\circ-3.60}{9.8 \times \cos 27^\circ}$

$\mu_k=0.097$

3 0

3 years ago

The drum shown in the figure has a radius of 0.40 m and a moment of inertia of 2.3 kg • m2 about an axis perpendicular to it thr

Citrus2011 [14]

The constant force applied to the rope is 7.72 N.

<h3>Net torque on the drum</h3>

The net torque on the drum is calculated as follows;

$Fr - F_fr = I \alpha$

Linear speed, v = ωr = 23 x 0.4 = 9.2 m/s

distance traveled = 14 m

<h3>Tangential acceleration</h3>

The acceleration of the drum is calculated as follows;

v² = u² + 2as

v² = 0 + 2as

v² = 2as

a = v²/2s

a = (9.2)/2(14)

a = 0.329 m/s²

<h3>Angular acceleration of the drum</h3>

$\alpha = \frac{a}{r} = \frac{0.329}{0.4} = 0.82 \ rad/s^2$

<h3>Applied force</h3>

The constant force applied to the rope is calculated as follows;

$Fr - F_fr = I \alpha\\\\Fr = I \alpha + F_fr\\\\F = \frac{ I \alpha + F_fr}{r} \\\\F = \frac{2.3(0.82) \ + \ 3(0.4)}{0.4} \\\\F = 7.72 \ N$

Learn more about net torque here: brainly.com/question/15262027

7 0

2 years ago

On planet Q the standard unit of volume is called guppi. Space travelers from Earth have determined that one liter = 38.2 guppie

ankoles [38]

Answer:

5730 guppies

Explanation:

1 liter= 38.2 guppies

150 liters= 150×38.2

8 0

3 years ago

Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa

ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

$v^2 - u^2 = 2*a*s$

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

$v^2 - 0 = 2 * 12.501 * 10$

$v = 15.812 m/s$

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.

5 0

4 years ago