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3 years ago

HELP PLEASE ............

Physics

1 answer:

Liono4ka [1.6K]3 years ago

7 0

1. solid
2. The molecules are tightly packed together so tha means there is less movement between the molecules.

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A 4 kW vacuum cleaner is powered by an electric motor whose efficiency is 90%. (Note that the electric motor delivers 4 W of net

RoseWind [281]

Answer: $3.6\ kW$

Explanation:

Given

Power Supplied $[tex]P_{input}=4\ kW$ [/tex]

Efficiency of the motor $\neta =90\%$

and $\neta =\dfrac{\text{Power output}}{\text{Power input}}$

$\Rightarrow 0.9=\dfrac{P_{out}}{4}$

$\Rightarrow P=0.9\times 4$

$\Rightarrow P=3.6\ kW$

So, vacuum cleaner delivers a power of $3.6\ kW$

3 0

2 years ago

An object with a mass 4.0 kg has a momentum of 64 kgm/s . How fast is the object traveling ?

Anastasy [175]

Answer:

The object will travel at the speed of 16 m/s.

Explanation:

Given

Mass m = 4.0 kg

Momentum p = 64 kgm/s

To determine

How fast is the object traveling?

<u>Important Tip:</u>

The product of the mass and velocity of an object — momentum.

Using the formula

$p = mv$

where

m = mass

v = velcity

p = momentum

Thus, in order to determine the speed of the object, all we need to do is to substitute p = 64 and m = 4 in the formula

$p = mv$

$64\:=\:4\times v$

switch the equation

$\:4\times \:v\:=64$

divide both sides by 4

$\frac{4v}{4}=\frac{64}{4}$

simplify

$v=16$ m/s

Therefore, the object will travel at the speed of 16 m/s.

3 0

2 years ago

What is an electrical charge how does it create electrical current

AveGali [126]

Answer:

Explanation:

The moving charged particles in an electric current are called charge carriers. In metals, one or more electrons from each atom are loosely bound to the atom, and can move freely about within the metal. These conduction electrons are the charge carriers in metal conductors.

The flow of electrons in a direction is known as electric current. The tendency of attraction between the positive and negative charges makes electric current flow through a wire

7 0

2 years ago

A resistor is connected in series with an AC source that provides a sinusoidal voltage of v of t is equal to V times cosine of b

nekit [7.7K]

<h2>Answer:</h2>

In circuits, the average power is defined as the average of the instantaneous power over one period. The instantaneous power can be found as:

$p(t)=v(t)i(t)$

So the average power is:

$P=\frac{1}{T}\intop_{0}^{T}p(t)dt$

But:

$v(t)=v_{m}cos(\omega t) \\ \\ i(t)=i_{m}cos(\omega t)$

So:

$P=\frac{1}{T}\intop_{0}^{T}v_{m}cos(\omega t)i_{m}cos(\omega t)dt \\ \\ P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}cos^{2}(\omega t)dt \\ \\ But: cos^{2}(\omega t)=\frac{1+cos(2\omega t)}{2}$

$P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}(\frac{1+cos(2\omega t)}{2} )dt \\\\P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}[\frac{1}{2}+\frac{cos(2\omega t)}{2}]dt \\\\P=\frac{v_{m}i_{m}}{T}[\frac{1}{2}(t)\right|_0^T +\frac{sin(2\omega t)}{4\omega} \right|_0^T] \\ \\ P=\frac{v_{m}i_{m}}{2T}[(t)\right|_0^T +\frac{sin(2\omega t)}{2\omega} \right|_0^T] \\ \\ P=\frac{v_{m}i_{m}}{2}$

In terms of RMS values:

$V_{RMS}=V=\frac{v_{m}}{\sqrt{2}} \\ \\ I_{RMS}=I=\frac{i_{m}}{\sqrt{2}} \\ \\ Then: \\ \\ P=VI$

7 0

2 years ago

In a closed system, _____ energy is equal to potential energy plus kinetic energy.

Kobotan [32]

The answer is mechanical

4 0

3 years ago

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