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enyata [817]
3 years ago
5

Someone help me please i need to finish this

Physics
2 answers:
Ilya [14]3 years ago
8 0

Answer:

D. A zinc Zn contains 30 protons inside the nucleus and 30 electron outside the nucleus

gavmur [86]3 years ago
5 0

Answer:

the last option is correct

Explanation:

see I won't explain all the points but will tell you the concept being used.

  • protons and neutrons are inside the nucleus in an atom while the electrons are outside the nucleus.

  • the mass number of an atom is equal to the sum of number of electrons and neutrons in an atom
  • atomic number is equal to the number of electrons which is equal to the number of protons in an atom
  • no. of electrons/ protons is always less than that of neutrons and they're almost equal( a large difference ain't obtained between the number of electrons and that of neutrons.

since, the rest of the options are violating the above rules they're incorrect

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What is the ideal mechanical advantage of the pulley system shown in this figure?
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Answer:

v

Explanation:

vv

4 0
3 years ago
A CD has a mass of 17 g and a radius of 6.0 cm. When inserted into a player, the CD starts from rest and accelerates to an angul
Stells [14]

Answer:

τ =9.41 * 10⁻⁴ N*m

Explanation:

Kinematics of the CD

The CD rotates with constant angular acceleration and its angular acceleration is calculated as follows:

\alpha = \frac{\omega_{f}- \omega_{i}}{t}   Formula (1)

Where:

α : angular acceleration. (rad/s²)

ωf: final angular velocity  (rad/s)

ωi : initial angular velocity  (rad/s)

t = time interval (s)

Data

ωf= 20 rad/s

ωi =0

t = 0.65 s.

Calculating of the angular acceleration of the CD

We replace data in the formula (1)

\alpha = \frac{20 -0}{0.65}

α  = 30.77 rad/s²

Newton's second law  in rotation:

F = ma has the equivalent for rotation:

τ = I * α   Formula  (2)

where:

τ : It is the net torque applied to the body.  (N*m)

I :  it is the moment of inertia of the body with respect to the axis of rotation (kg*m²)

α : It is angular acceleration. (rad/s²)

Calculating of the moment of inertia  of the CD

The moment of inertia of a disk with respect to an axis perpendicular to the plane  and passing through its center is calculated by the following formula:

I = (1/2) M*R² Formula (3)

Data

M= 17 g = 17/1000 kg = 0.017 kg  : CD mass

R= 6.0 cm= 6/100 m = 0.06 m : CD  radius

We replace data in the formula (3) :

I = (1/2) ( 0.017 kg)*(0.06 m)² = 3.06 * 10⁻⁵ kg*m²

Calculating of the  net torque acting on the CD

Data

α  = 30.77 rad/s²

I =  3.06 * 10⁻⁵ kg*m²

We replace data in the formula (2) :

τ = I * α

τ =( 3.06 * 10⁻⁵ kg*m²) * (30.77 rad/s²)

τ =9.41 * 10⁻⁴ N*m

3 0
3 years ago
What’s the mathematical relation between them
Gekata [30.6K]

Explanation:

there is no relationship between small mass and the bigger mass, but it can be related with the acceleration. Since Force is constant, acceleration is inversely proportional to the mass. Greater the mass, lesser is the acceleration and vise versa

6 0
3 years ago
A projectile is fired upward at an angle θ above the horizontal with an initial speed v0. At its maximum height, what are its ve
aliya0001 [1]

Answer:

\vec{v}_{\rm max} = v\cos(\theta)(\^x)\\|\vec{v}_{\rm max}| = v\cos(\theta)\\\vec{a} = \vec{g} = -9.8\^y

Explanation:

The equations of kinematics will be used to solve this question:

y - y_0 = v_{y_0}t + \frac{1}{2}a_yt^2\\v_y^2 = v_{y_0}^2 + 2a_y(y - y_0)\\v_y = v_{y_0} + a_yt

At its maximum height, the projectile has zero velocity in the y-direction. But its velocity in the x-direction is unaffected.

First, let's apply the above equations to the x-direction.

There is no acceleration in the x-direction. So, its velocity in the x-direction is constant during the motion.

v_x = v_{x_0} + a_xt = v_{x_0} + 0\\v_x = v_{x_0} = v\cos(\theta)

Therefore, the velocity vector of the projectile is

v_{max} = v_x = v\cos(\theta)

The speed of the projectile is the same.

The acceleration vector is constant during the motion and equal to the gravitational acceleration, which is -9.8 downwards.

7 0
4 years ago
Which phrases describe all the outer planets motion? Select two options
11111nata11111 [884]

Answer:

slow revolution and  fast rotation

Explanation:

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