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3 years ago

Explain 2 reasons it is wise to use energy-efficient electric appliances.

Physics

1 answer:

Free_Kalibri [48]3 years ago

3 0

<h2>reasons- instead of two,i got you five</h2>

1.Energy efficiency saves you money.

2.Energy efficiency improves the economy.

3.Energy efficiency is good for the environment.

4.Energy efficiency improves national security.

5.Energy efficiency enhances quality of life.

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Give reason The SI system of unit is better than the MKS system

egoroff_w [7]

Answer:

The SI was and is intended to extend and refine the definitions used by the MKS.

6 0

3 years ago

A 5.0 kg box is sliding across a waxed floor by the application of a 15 N east force. If the force of friction is 2.5 N west, wh

coldgirl [10]

1) 12.5 N east

There are two forces acting on the box along the horizontal direction:

- The applied force of 15 N east, we indicate it with F

- The force of friction of 2.5 N west, we indicate it with $F_f$

Taking east as positive direction, we can write the two forces has

$F=+15 N\\F_f = -2.5 N$

Therefore, the net force on the box will be:

$F_{net} = F + F_f = 15 + (-2.5) = +12.5 N$

And the positive sign means the direction is east.

2) $2.5 m/s^2$

We can solve this part by using Newton's second law:

$F_{net}=ma$

where

$F_{net}$ is the net force on the box

m is its mass

a is the acceleration

For the box in this problem,

$F_{net} = 12.5 m/s^2$ (east)

m = 5.0 kg

Solving for a, we find the acceleration:

$a=\frac{F_{net}}{m}=\frac{12.5}{5.0}=2.5 m/s^2$

And the direction is the same as the net force (east)

6 0

4 years ago

What is the relationship between elevation and energy

jasenka [17]

The Energy related to object motion.Potential energy most commonly refers to gravitational potential energy, which is energy associated with an object's elevation. For an object of mass m and elevation z, its potential energy is mgz where g is the gravitational constant .............. HOPE IT HELPS YOU :)

7 0

3 years ago

What is the approximate radius of the n = 1orbit of gold ( Z<br> =19 )?

Serjik [45]

Answer:

$r=6.72\times 10^{-13}\ m$

Explanation:

Let r is the radius of the n = 1 orbit of the gold. According to Bohr's model, the radius of orbit is given by :

$r=\dfrac{n^2h^2\epsilon_o}{Z\pi me^2}$

Where

n = number of orbit

h = Planck's constant

Z = atomic number (for gold, Z = 79)

m = mass of electron

e = charge on electron

$r=\dfrac{(6.63\times 10^{-34})^2 \times 8.85\times 10^{-12}}{79\pi \times 9.1\times 10^{-31}\times (1.6\times 10^{-19})^2}$

$r=6.72\times 10^{-13}\ m$

So, the radius of the n = 1 orbit of gold is $6.72\times 10^{-13}\ m$ . Hence, this is the required solution.

4 0

4 years ago

Leon sees a poster that shows a lake in front of a snow-capped mountain. The mountain appears upside down in the lake. Which bes

arsen [322]

Answer: The correct answer is "The surface of the lake is smooth".

Explanation:

The light gets reflected from the smooth surface at the same angle as it hits that surface. If the light gets reflected in all direction from the rough surface when it hits the surface. Then, there will be diffuse reflection.

In the given problem, Leon sees a poster that shows a lake in front of a snow-capped mountain. The mountain appears upside down in the lake. Here, the water acts like a mirror. The light rays incident on the surface of the water from the mountain then the reflected rays get reflected back from the smooth surface of the lake. Here, the angle of incidence is equal to the angle of the reflection.

One can see the image of the object on the surface of the lake.

Therefore, the correct option is (A).

4 0

3 years ago

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