Machines can be made more efficient by reducing __________________

Work out the current through an electric kettle with a power of 2.2 kW if it uses the 180 V mains supply. Round your answer to 2

weeeeeb [17]

Answer:

12 A

Explanation:

Given,

Power of electric kettle=2.2 kW=2200W (since 1kW=1000W)

Voltage=180V

Current=?

Power = Voltage*Current

Current = Power ÷ Voltage

=2200W ÷ 180V

=12.22 Ampere

=12 A

7 0

3 years ago

Star a has an absolute magnitude of 8. what is its apparent magnitude at a distance of 100 pc

tresset_1 [31]

From the definition of apparent magnitude, we know that:
$m_{1} - m_{2} = -2.5Log( \frac{F_{1}}{F_{2}} )$
where:
m = apparent magnitude
F = corresponding flux

We also know that the flux is given by the formula:
$F = \frac{L}{4 \pi d^{2} }$
where:
L = luminosity
d = distance

Therefore:
$\frac{F_{1} }{F_{2}} = (\frac{L_{1} }{4 \pi d_{1}^{2} })(\frac{4 \pi d_{2}^{2} }{L_{2} }) \\ = \frac{L_{1}d_{2}^{2}}{L_{2}d_{1}^{2}}$

Now, let's apply these formulae to the same star (therefore, same luminosity), using apparent magnitude and absolute magnitude (which is defined as the apparent magnitude the star would have if it were at a distance of 10pc):
$m - M = 2.5 Log ( \frac{d}{10pc})^{2}$

Now, let's solve for m:
$m = M + 2.5 Log ( \frac{d}{10})^{2}$
= <span> $8 + 2.5 Log ( \frac{100}{10})^{2}$ </span>
= 13

Hence, the apparent magnitude of the star would be m = +13

3 0

4 years ago

In order for work to be done, what three things are necessary?

andrey2020 [161]

The three things that are necessary are power, a force, and movement in the opposite direction of the applied force.

6 0

3 years ago

Read 2 more answers

Suppose you must design an experiment to test how a paper airplane's shape affects the distance it will fly. Your plane must fly

Rina8888 [55]

Answer:

Explanation:

Your plane must fly halfway across your classroom to get the best grade. The teacher reminds you to use both imagination and logical reasoning in your design. Write a procedure for an experiment that tests how a paper airplane's shape affects the distance it will fly. Then, describe how you might use both ...

5 0

3 years ago

Read 2 more answers

A transverse, travelling wave on a chord is represented by = 0.22sin (5.6 + 34) where and are in meters and is in seconds. For t

Neko [114]

Answer:

A) 1.122 m

B) 5.4 hertz

C) 6.06 m/s ( towards negative x axis )

D) 0.22

E) max speed = amplitude * 34

= 0.22 * 34 = 7.48

minimum speed ( speed at rest ) = 0

Explanation:

The travelling wave = D = 0.22sin ( 5.6x + 34t)

this wave is represented in the form : D = Asin ( kx + wt)

A) wavelength

k = 2 $\pi$ / v

v = wavelength

k = 5.6

therefore wavelength ( v ) from the equation = 2 $\pi$ / 5.6 = 1.122 m

B ) frequency

w = 2 $\pi$ f

w = 34

f = frequency

therefore f = w / 2 $\pi$ = 34 / 2 $\pi$ = 5.4 hertz

C ) velocity

speed = f v

v = 5.4 * 1.122 = 6.06 m/s ( towards negative x axis )

D) amplitude

A = 0.22

E ) maximum and minimum speeds of particles on the chord

max speed = amplitude * 34

= 0.22 * 34 = 7.48

minimum speed ( speed at rest ) = 0

5 0

3 years ago

Machines can be made more efficient by reducing ___________________.