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allochka39001 [22]
3 years ago
14

What is power in physics​

Physics
1 answer:
Shkiper50 [21]3 years ago
8 0

Edit

In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Having no direction, it is a scalarquantity. In the International System of Units, the unit of power is the joule per second (J/s), known as the watt in honour of James Watt, the eighteenth-century developer of the condenser steam engine. Another common and traditional measure is horsepower (comparing to the power of a horse). Being the rate of work, the equation for power can be written:

Power

Common symbols

Derivations from

other quantities

P = E/t

P = F·v

P = V·I

P = T·ω

As a physical concept, power requires both a change in the physical system and a specified time in which the change occurs. This is distinct from the concept of work, which is only measured in terms of a net change in the state of the physical system. The same amount of work is done when carrying a load up a flight of stairs whether the person carrying it walks or runs, but more power is needed for running because the work is done in a shorter amount of time.

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A worker is thinking about two ways to get a box up 1.2 m onto a loading dock. He can use a force of 250 N to lift it straight u
harina [27]

Answer:

<em>The second option has a lower power output. P=30 W</em>

Explanation:

<u>Mechanical Power </u>

It is a physical magnitude that measures the rate a work W is done over time t.

\displaystyle P=\frac{W}{t}

Since W=F.d

\displaystyle P=\frac{F.d}{t}

The first option means the worker will lift the box by a distance of 1.2 meters in 3 seconds by applying 250 N of force. That produces a power of

\displaystyle P=\frac{(250). (1.2)}{3}=100\ Watt

The second option requires the worker applies 75 N of force and travel a distance of 4 meters for 10 seconds, thus the power is

\displaystyle P=\frac{(75). (4)}{10}=30\ Watt

The second option has a lower power output

7 0
3 years ago
A boy is pulling a cart by a force of 100N. The frictional force experienced by the cart is 20N. The force causing the motion of
Serga [27]

Answer:

3 is right i guss look : 100N-20N=80N

4 0
2 years ago
Suppose an automobile has 2000-joules of kinetic energy. when it moves at twice the speed, what will be its kinetic energy? what
NeX [460]

Answer:

K.Eₓ = 4 K.E

K.Eₓ = 9 K.E

Explanation:

Th formula for the kinetic energy of a body is given as follows:

K.E = \frac{1}{2}mv^2\\   ---------------equation (1)

where,

K.E = Kinetic Energy of Automobile

m = mass of automobile

v = speed of automobile

For twice speed:

vₓ = 2v

then,

K.E_{x} = \frac{1}{2}mv_{x}^2\\K.E_{x} = \frac{1}{2}m(2v)^2\\K.E_{x} = 4\frac{1}{2}mv^2\\

using equation (1):

<u>K.Eₓ = 4 K.E</u>

For thrice speed:

vₓ = 3v

then,

K.E_{x} = \frac{1}{2}mv_{x}^2\\K.E_{x} = \frac{1}{2}m(3v)^2\\K.E_{x} = 9\frac{1}{2}mv^2\\

using equation (1):

<u>K.Eₓ = 9 K.E</u>

6 0
3 years ago
To practice problem-solving strategy 26.1 resistors in series and parallel. two bulbs are connected in parallel across a source
hichkok12 [17]
Emf e = 11
r 1 = 3.0
r 2 = 3.0
r 3 = ?

The two in parallel are equivalent to 3 • 3/6 = 1.5 Ω 
To have 2.4 volts across them, the current is I = 2.4/1.5 = 1.6 amps. and the unknown R = (11–2.4) / 1.6 = 5.375 Ω or 5.4 Ω 
3 0
3 years ago
Find the current in the thin straight wire if the magnetic field strength is equal to 0.00005 T at distance 5 cm. ​
Elodia [21]

Answer:

Answer

Correct option is

A

5×10

−6

tesla

I=5A

x=0.2m

Magnetic field at a distance 0.2 m away from the wire.

B=

2πx

μ

0

I

=

2π×0.2

4π×10

−7

×5

=10×5×10

−7

=5×10

−6

tesla

3 0
3 years ago
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