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4 years ago

What is described by the terms body-centered cubic and face-centered cubic?

Physics

1 answer:

Montano1993 [528]4 years ago

7 0

In physical chemistry, the terms body-centered cubic (BCC) and face-centered cubic (FCC) refer to the cubic crystal system of a solid. Each solid is made up simple building blocks called lattice units. There are different layouts of a lattice unit.

It is better understood using 3-D models shown in the picture. A BCC unit cell has one lattice point in the center, together with eight corner atoms which represents 1/8 of an atom. Therefore, there are 1+ 8(1/8) = 2 atoms in a BCC unit cell. On the other hand, a FCC unit cell is composed of half of an atom in each of its faces and 1/8 of an atom in its corners. Therefore, there are (1/2)6 + (1/8)8 = 4 atoms in a FCC unit cell.

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A vehicle moving along at 5m/s. What should be the constant deceleration in order to stop it within 15m?

Oduvanchick [21]

Answer:

a = -5/6 m/s²

Explanation:

v² = u² + 2as

a = (v² - u²) / 2s

a = (0² - 5²) / 2(15)

a = -5/6 m/s²

This assumes the initial velocity was in the positive direction.

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3 years ago

An airplane awaiting departure is cleared to takeoff, its accelerates down a runway at 3.20m/ s2 for 32.8s until it finally lift

stich3 [128]

The final velocity before takeoff is 104.96 m / s.

<u>Explanation:</u>

The last velocity of a given object over some time defines the final velocity. The final velocity of the object is given by the product of acceleration and time and adding this product to the initial velocity.

To calculate the final velocity,

V = u + at

where v represents the final velocity,

u represents the initial velocity,

a represents the acceleration

t represents the time taken.

$v = 0 + (3.20)\times( 32.8)$

v = 104.96 m / s.

7 0

3 years ago

Why is Carbon Tetrahydride a covalent bond? plzzz helpppp!!!!!!

arlik [135]

Answer:

carbon has four unpaired electrons in its valence shell . hydrogen having one unpaired electron in its valence shell comes to bond with carbon by sharing a pair of electrons .since carbon needs 4 electrons to be stable, 4 hydrogen atoms take part in the bond . It's a covalent bond because the difference between the electronegativity of carbon and hydrogen is quite small .

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3 years ago

A catapult with a radial arm 3.81 m long accelerates a ball of mass 18.2 kg through a quarter circle. The ball leaves the appara

saw5 [17]

Answer:

(a) $\alpha = 53.73 m/s^2$

(b) I =428 $kgm^2$

(c) $\tau = 428 \times 53.73 = 22996 .44Nm$

Explanation:

GIVEN

mass = 18.2 kg

radial arm length = 3.81 m

velocity = 49.8 m/s

mass of arm = 22.6 kg

we know using relation between linear velocity and angular velocity

$\omega = \frac{v}{l}$

$\omega = \frac{49.8}{3.81} \\\omega = 12.99 rad/s$

for angular acceleration, use the following equation.

$\omega _{f}^2 = \omega_{i}^2+2\alpha\theta$

since $\omega _{i} = 0$

here for one circle is 2 π radians. therefore for one quarter of a circle is π/2 radians

so for one quarter $\theta = \frac{\pi }{2}$

$(12.99)^2 = 2\alpha(\frac{\pi }{2})$

on solving

$\alpha = \frac{168.74}{\pi }\\\alpha = 53.73 m/s^2$

(b)

For the catapult,

moment of inertia

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

$I = \frac{1}{2} \times 22.6\times 3.81 \times 3.81\I = 164kg m^2$

For the ball,

$I = MR^2$

$I = 18.2 \times 14.51$

$I = 264 kgm^2$

so total moment of inertia = 428 $kgm^2$

(c)

$\tau = I\alpha$

$\tau = 428 \times 53.73 = 22996 .44Nm$

3 0

4 years ago

The parallax method of measuring star distances gives most accurate results when the gap between two observations of a star is a

EleoNora [17]

<span>b. It ensures that measurements are taken from two points
that are very far apart.

Measurements taken six months apart are the farthest apart
that an astronomer can ever get ... they're on opposite sides
of the Earth's orbit !</span>

8 0

3 years ago

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