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kozerog [31]
3 years ago
9

2. Elements in the same group have similar properties because they have O the same number of protons O the same number of valenc

e electrons O the same number of energy levels with electrons O the same total number of electrons​
Physics
1 answer:
NARA [144]3 years ago
3 0
The same number of valence electrons
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A bullet with mass m = 0.1 kg grams hits a ballistic pendulum with length L = 3 meters and mass M = 2 kg and lodges in it. When
Mnenie [13.5K]

Answer:

e)     v₁ = 29.7 m / s

Explanation:

Let's propose the solution of the problem, let's start at the moment

Initial

        p₀ = m v₁

Final

     p_{f} = (m + M) v

The moment is preserved

      p₀ =  p_{f}

      m v₁ = (m + M) v

      v = m / (m + M) v₁        (1)

a) energy is conserved

Let's look for kinetic energy

Initial

      K₀ = ½ m v₁²

Final

      K_{f} = ½ (m + M) v²

Let's replace v

     K_{f} = ½ (m + M) [m / (m + M) v₁]²

      K_{f} = ½ m² / (m + M) v₁²

Let's look for the relationship of these energies

     Ko / K_{f} = ½ m v₁² / (½ m² / (m + M) v₁²)

     Ko / K_{f}= (m + M) / m = (1 + M / m)²

The kinetic energy changes therefore it is not conserved in the process, the missing energy is converted into potential heat energy during the crash

b) The impulse is conserved because the system is defined as formed by the two bodies and the externals are of action and reaction, so for the complete system the sum is zero and the moment does not change in value

c) in this case the system is already formed by the two bodies and since there is no rubbing the mechanical energy is conserved, transforming from kinetics to potential

d) when the pendulum oscillates the speed changes from v to zero, so the moment is not conserved, this is because there is an external force acting on the system, the force of gravity

e) For this part let's start at the end of the movement

It is system (bullet + block) moves, energy is conserved

Final. Highest point

          Em_{f} = U = (m + M) g h

Initial. Lowest point

          Em₀ = K = ½ (m + M) v2

          Em₀ =  Em_{f}

          ½ (m + M) v² = (m + M) g h

          v = √ 2gh

Let's look for the height (h) by trigonometry

         Cos 15 = x / L

          h = L-x

          h = L - L cos 15

          h = L (1- cos 15)

We replace

          v = √ (2gL (1- cos 15))

Now we use equation (1) of momentum conservation

         v = m / (m + M) v1

         v₁ = (m + M) / m v

         v1 = (0.1 +2.0) /0.1 RA (2 9.8 3 (1- cos 15))

         v₁ = 21 √ (2.00)

        v₁ = 29.7 m / s

6 0
3 years ago
Sound waves are mechanical waves in which the particles in the medium vibrate in a direction parallel to the direction of energy
mel-nik [20]
<span>longitudinal waves

Hope this helps!</span>
6 0
3 years ago
A 500N load is lifted to a height in 50 sec. Calculate the power.
Alika [10]

Answer:

25000w

Explanation:

P=Fxs

p=500×50

p=25000 watts

7 0
3 years ago
An electron is trapped between two large parallel charged plates of a capacitive system. The plates are separated by a distance
Nataly_w [17]

Answer:

0.4cm

Explanation:

First, you calculate the dis acceleration of the electron generated by the potential difference between the plates:

F=ma\\\\qE=ma\\\\q\frac{V}{d}=ma\\\\a=\frac{qV}{md}    (1)

q: charge of the electron = 1.6*10^-19 C

V: potential difference between plates = 100V

m: mass of the electron

d: distance between parallel plates = 1cm = 0.01m

by replacing the values of the parameters you obtain:

a=\frac{(1.6*10^{-19C})(100V)}{(9.1*10^{-31})(0.01m)}=1.75*10^{15}\frac{m}{s^2}

you use this value in the following kinematic equation:

v^2=v_o^2-2ax    (2)

v: final velocity = 0m/s (until the electron stops)

from the equation (2) you calculate x, the distance traveled by the electron. But before you calculate the initial velocity of the electron by using the following equation:

K=10eV\\\\\frac{1}{2}mv_o^2=10eV\\\\v_o=\sqrt{\frac{2(10(1.602*10^{-19}J))}{9.1*10^{-31}kg}}\\\\v_o=1.87*10^6\frac{m}{s}

Next, you replace vo in (2) to obtain x:

0=v_o^2-2ax\\\\x=\frac{v_o^2}{2a}=\frac{(1.87*10^6m/s)^2}{2(1.75*10^{15}m/s^2)}=0.001m=0.1cm

Then, the electron travels 0.1cm from the middle of the region between the parallel plates, hence, the distance between the electron and the negatve plate is:

0.5cm-0.1cm=0.4cm

6 0
4 years ago
Some girls use a curling iron to fix their hair. It is very hot when plugged in for a while. If you want protect your skin, you
MakcuM [25]

Answer:

B. Insulates thermal energy

8 0
3 years ago
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