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3 years ago

In order to change power, what else must be changed?

2 answers:

6 0

<span>In order to change power, current or voltage should also be changed. Voltage is an electromotive force, and also the quantitative expression that shows the potential difference of the two points charged in an electrical field. So, before power will take place, it would always be best to change also the voltage.</span>

LenaWriter [7]3 years ago

4 0

Answer:

In order to change electrical power, current or voltage or both current and voltage should be changed.

for changing mechanical power, work or time or both should be change

Explanation:

Electrical power

We know that electrical power is given by following equation

$power=current\times voltage$

therefore, power depends on current and voltage and to change power, current or voltage or both current and voltage should be changed

Mechanical power

also mechanical power is given as

Power= $\frac{work}{time}$

therefore for changing mechanical power work and time should be change

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Consider an isolated system, by which we mean a system free of external forces. If the sum of the particle energies in the syste

Airida [17]

Answer:

The system's potential energy is -147 J.

Explanation:

Given that,

Energy = 147 J

We know that,

System is isolated and it is free from external forces.

So, the work done by the external forces on the system should be equal to zero.

$W=0$

We need to calculate the system's potential energy

Using thermodynamics first equation

$\Delta U=W-\Delta E$

Put the value into the formula

$\Delta U=0-147$

$\Delta U=-147\ J$

Hence, The system's potential energy is -147 J.

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2 years ago

Problem: A barbell consists of two small balls, each with mass m at the ends of a very low mass rod of length d. The barbell is

zepelin [54]

Answer:

mass of ball 1=m1

mass of ball 2=m2

velocity of ball=r1w1

velocity of ball 2=r2w2

Total angular momentum=m1*v1+m2*v2

but

v1=r1*w1

v2=r2*w2

Substitute values in above equation

Total angular momentum of the system=m1*r1*w1+m2*r2*w2

7 0

3 years ago

Heat transfers energy from a hot object to a cold object. Both objects are isolated from their surroundings. The change in entro

aniked [119]

To develop this problem we will start from the definition of entropy as a function of total heat, temperature. This definition is mathematically described as

$S = \frac{Q}{T}$

Here,

Q = Total Heat

T = Temperature

The total change of entropy from a cold object to a hot object is given by the relationship,

$\Delta S = \frac{Q}{T_{cold}}-\frac{Q}{T_{hot}}$

From this relationship we can realize that the change in entropy by the second law of thermodynamics will be positive. Therefore the temperature in the hot body will be higher than that of the cold body, this implies that this term will be smaller than the first, and in other words it would imply that the magnitude of the entropy 'of the hot body' will always be less than the entropy 'cold body'

Change in entropy $\Delta S_{hot}$ is smaller than $\Delta S_{cold}$

Therefore the correct answer is C. Will always have a smaller magnitude than the change in entropy of the cold object

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2 years ago

A firefighter of mass 81 kg slides down a vertical pole with an acceleration of 3 m/s 2 . The acceleration of gravity is 10 m/s

natima [27]

Answer:

The force of friction that acts on him is

$F_k=567N$

Explanation:

The firefighter with an acceleration of 3m/s^2 take the gravity acceleration as 10m/s^2 isn't necessary to know the coefficient of friction just to know the force of friction:

$F=m*a$