Ask question

Ask question

All categories

2 years ago

10

Electrical energy is used to turn the blades of a fan. The amount of energy transformed is seen here : 750 J electrical energy i

s transformed into 400 J kinectic energy . What happened to the remaining 350j of energy?

1 answer:

Charra [1.4K]2 years ago

3 0

Electrical energy is used to run the fan

Here as per given condition 750 J of electrical energy is used to run the fan which is converted into Kinetic energy as 400 J

So here we can see that 350 J of energy is lost against many other type of frictional and resistive loses.

So here we can say that out of 750 J of energy only 400 J is used to run the fan and rest amount of energy is lost against friction.

also we can say that efficiency of this fan will be

$\eta = \frac{Useful}{Total}$

$\eta = \frac{400}{750}$

$\eta = \frac{8}{25}$

You might be interested in

A 50 kg runner runs up a flight of stairs. The runner starts out covering 3 steps every second. At the end the runner stops. Thi

nadezda [96]

To solve the problem it is necessary to take into account the concepts of kinematic equations of motion and the work done by a body.

In the case of work, we know that it is defined by,

$W = F * d$

Where,

F= Force

d = Distance

The distance in this case is a composition between number of steps and the height. Then,

$d=h*N$ , for h as the height of each step and N number of steps.

On the other hand we have the speed changes, depending on the displacement and acceleration (omitting time)

$V_f^2-V_i^2 = 2a\Delta X$

Where,

$V_f =$ Final velocity

$V_i =$ Initial Velocity

a = Acceleration

$\Delta X =$ Displacement

PART A) For the particular case of work we know then that,

$W = F*d$

$W = m*g*(h*N)$

$W = 50*9.8*(0.3*30)$

$W = 4.41kJ$

Therefore the Work to do that activity is 4.41kJ

PART B) To find the acceleration (from which we can later find the time) we start from the previously given equation,

$V_f^2-V_i^2 = 2a\Delta X$

Here,

$V_i = \frac{0.3*3}{1} = 0.90m/s\rightarrow$ 3 steps in one second

$v_f = 0$

Replacing,

$V_f^2-V_i^2 = 2a\Delta X$

$0-0.9^2=2a(30*0.3)$

Re-arrange for a,

$a = -\frac{0.9^2}{2*30*0.3}$

$a = -45*10^{-3}m/s^2$

At this point we can calculate the time, which is,

$t = \frac{\Delta V}{a}$

$t = \frac{0-0.9}{-45*10^{-3}}$

$t = 20s$

With time and work we can finally calculate the power

P = \frac{W}{t} = \frac{4.41}{20}

P = 0.2205kW

6 0

3 years ago

(6.MS-ETS2-1(MA).) The electrons in __________ move about more freely than the electrons in insulators which is why this type of

Tresset [83]

Answer:

A) conductors

Explanation:

A conductor can be defined as any material or object that allows the free flow of current or electrons (charge) in one or more directions in an electrical circuit. Some examples of a conductor are metals, tungsten, copper, aluminum, iron, graphite, etc.

Basically, the main purpose of a conductor in physics is to provide a low-resistance path between electrical circuits or components. This low-resistance path is to ensure that the electrical components allows the free flow of electrons and thus, enabling charge transfer.

Hence, the electrons in conductors move about more freely than the electrons in insulators which is why this type of material can be used to create electric circuits because it would significantly provide a low-resistance path between the electric circuits.

8 0

2 years ago

From the list below, which name appears in two different parts of the body? *

Kisachek [45]

Answer:

Ngjfibfubbb

Explanation:

7 0

2 years ago

Explain why wine glasses with long stems have broad base

Anna35 [415]

Answer:

The best glasses have a wider bowl than rim to allow for proper swirling. The swirl releases volatile aroma compounds and creates a vortex in the center of the glass towards which these compounds are drawn

Explanation:\\\

6 0

2 years ago

g An electric hot plate raises its own internal energy and the internal energy of a cup of water by 9000J, and there is at the s

DochEvi [55]

Answer:

11700j

Explanation:

add the two because the plate has to maintain the temp.

2700+9000=11700

3 0

2 years ago