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3 years ago

Which method is used to deliver heat in most central heating systems?

Physics

2 answers:

Wewaii [24]3 years ago

5 0

Theu use convection currents to blow the air aroubd the house

inessss [21]3 years ago

4 0

The right answer is B. hope this helps you :)

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Four objects are situated along the y axis as follows: a 1.99-kg object is at 2.99 m, a 2.96-kg object is at 2.57 m, a 2.43-kg o

Dominik [7]

Answer:

The center of mass for the object is $y_c = 1.063 \ m$ from the origin

Explanation:

From the question we are told that

The mass of the first object is $m_1 = 1.99 \ kg$

The position of first object with respect to origin $y_1 = 2.99 \ m$

The mass of the second object is $m_2 = 2.96 \ kg$

The position of second object with respect to origin $y_2 = 2.57 \ m$

The mass of the third object is $m_3 = 2.43 \ kg$

The position of third object with respect to origin $y_3 = 0 \ m$

The mass of the fourth object is $m_3 = 3.96 \ kg$

The position of fourth object with respect to origin $y_3 = -0.502 \ m$

Generally the center of mass of the object along the x-axis is zero because all the mass lie on the y axis

Generally the location of the center mass of the object is mathematically represented as

$y_c = \frac{m_1 * y_1 + m_2 * y_2 + m_3 * y_3 + m_4 * y_4}{m_1 + m_2 + m_3 + m_4}$

=> $y_c = \frac{1.99 * 2.99 + 2.96 * 2.57 + 2.43 * 0 + 3.96 * (-0.502)}{1.99+ 2.96 + 2.43 + 3.96}$

=> $y_c = 1.063 \ m$

3 0

3 years ago

Arigid body must rotate about an axis in order for it to have angular momentum about that axis. True False

kompoz [17]

Answer:

False

Explanation:

Let's consider the definition of the angular momentum,

$\vec{L} = I \vec{\omega}$

where $I = \int\limits_m r^2 dm = \lim_{n \to \infty} \sum\limits_{i=1}^n m_i r_i^2$ is the moment of inertia for a rigid body. Now, this moment of inertia could change if we change the axis of rotation, because "r" is defined as the distance between the puntual mass and the nearest point on the axis of rotation, but still it's going to have some value. On the other hand,

$\vec{\omega} = \frac{\vec{r} \times \vec{v}}{r^2}$ so $\vec{\omega} \neq 0$ unless $\vec{r}$ ║ $\vec{v}$ .

In conclusion, a rigid body could rotate about certain axis, generating an angular momentum, but if you choose another axis, there could be some parts of the rigid body rotating around the new axis, especially if there is a projection of the old axis in the new one.

7 0

3 years ago

Match the theory to the statement that best describes it. 1. big bang. 2. steady state. 3.osscillating universe. 4. inflation Ch

Gre4nikov [31]

Explanation :

(1) Big bang : (1) The most accepted theory on the origin of the universe.

This theory shows the expanding of the universe from high density and high-temperature states.

(2) Steady state : (3) All is the same and will always stay the same.

Steady state means that the properties of any system remain the same always.

(3) Oscillating universe : (4) Agrees with the big bang theory but insists the universe expanded much quicker.

Oscillating universe theory is the result of big bang theory.

(4) Inflation Choices : (2) it's like an inflating and deflating balloon that never stops.

In cosmology, cosmic inflation or deflation is just the expanding and contraction of the universe.

So, the statements and the choices are related as:

(1)-(1)

(2)- (3)

(3)-(4)

(4)-(2)

8 0

3 years ago

Read 2 more answers

What happens when infrared hits a shiny surface

saw5 [17]

Will reflect ........

3 0

3 years ago

A crime suspect fled the scene when police officers entered the building. How far could he run in 10 minutes if he can run 5 mil

emmainna [20.7K]

(5 mi/hr) x (1hr/60min) x (10min) = 5 x 10 / 60 = <em>5/6 mile</em>

(5/6 mile) x (1,760 yd/mile) = <em>1,466 and 2/3 yards</em>

3 0

3 years ago