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3 years ago

5

Nichrome is used in electric heater cooker because_________.

2 answers:

Maurinko [17]3 years ago

8 0

Resistivity of nichrome is high.

Vesnalui [34]3 years ago

4 0

Explanation:

2.Resistivity of nichrome is high

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A small rock is thrown straight up with initial speed v0 from the edge of the roof of a building with height H. The rock travels

Crank

Answer:

$v_{avg}=\dfrac{3gH+v_0^2}{v_0+\sqrt{v_0^2+2gH} }$

Explanation:

The average velocity is total displacement divided by time:

$v_{avg} =\dfrac{D_{tot}}{t}$

And in the case of vertical $v_{avg}$

$v_{avg}=\dfrac{y_{tot}}{t}$

where $y_{tot}$ is the total vertical displacement of the rock.

The vertical displacement of the rock when it is thrown straight up from height $H$ with initial velocity $v_0$ is given by:

$y=H+v_0t-\dfrac{1}{2} gt^2$

The time it takes for the rock to reach maximum height is when $y'(t)=0$ , and it is

$t=\frac{v_0}{g}$

The vertical distance it would have traveled in that time is

$y=H+v_0(\dfrac{v_0}{g} )-\dfrac{1}{2} g(\dfrac{v_0}{g} )^2$

$y_{max}=\dfrac{2gH+v_0^2}{2g}$

This is the maximum height the rock reaches, and after it has reached this height the rock the starts moving downwards and eventually reaches the ground. The distance it would have traveled then would be:

$y_{down}=\dfrac{2gH+v_0^2}{2g}+H$

Therefore, the total displacement throughout the rock's journey is

$y_{tot}=y_{max}+y_{down}$

$y_{tot} =\dfrac{2gH+v_0^2}{2g}+\dfrac{2gH+v_0^2}{2g}+H$

$\boxed{y_{tot} =\dfrac{2gH+v_0^2}{g}+H}$

Now wee need to figure out the time of the journey.

We already know that the rock reaches the maximum height at

$t=\dfrac{v_0}{g},$

and it should take the rock the same amount of time to return to the roof, and it takes another $t_0$ to go from the roof of the building to the ground; therefore,

$t_{tot}=2\dfrac{v_0}{g}+t_0$

where $t_0$ is the time it takes the rock to go from the roof of the building to the ground, and it is given by

$H=v_0t_0+\dfrac{1}{2}gt_0^2$

we solve for $t_0$ using the quadratic formula and take the positive value to get:

$t_0=\dfrac{-v_0+\sqrt{v_0^2+2gH} }{g}$

Therefore the total time is

$t_{tot}= 2\dfrac{v_0}{g}+\dfrac{-v_0+\sqrt{v_0^2+2gH} }{g}$

$\boxed{t_{tot}= \dfrac{v_0+\sqrt{v_0^2+2gH} }{g}}$

Now the average velocity is

$v_{avg}=\dfrac{y_{tot}}{t}$

$v_{avg}=\dfrac{\frac{2gH+v_0^2}{g}+H }{\frac{v_0+\sqrt{v_0^2+2gH} }{g} }$

$\boxed{v_{avg}=\dfrac{3gH+v_0^2}{v_0+\sqrt{v_0^2+2gH} } }$

5 0

3 years ago

A car has 10000kg starts from rest and attains velocity of 20m/s in 5 seconds find the force

Rasek [7]

Ewan ko po ehh sorri po’ hahaha thanks me

7 0

3 years ago

A proton at location A makes an electricfield E-->1 atlocation B. A different proton, placed atlocation B, experiences a forc

luda_lava [24]

Answer:

Explanation:

|F-->1| = E-->1 x charge on proton

= 300 x 1.6 x 10⁻¹⁹

Magnitude of electric force on proton

|F-->1| = 480 x 10⁻¹⁹ N .

Inside lithium nucleus , there are three protons so charge on it

= 3 x 1.6 x 10⁻¹⁹ = 4.8 x 10⁻¹⁹ C .

Magnitude of electric force on lithium nucleus

|F-->Li| = E-->1 x charge on lithium nucleus

= 300 x 4.8 x 10⁻¹⁹

= 1440 x 10⁻¹⁹ N .

Electron has same charge as that possessed by proton so charge on electron = 1.6 x 10⁻¹⁹ C

Magnitude of force on electron

|F-->1| = E-->1 x charge on electron

= 300 x 1.6 x 10⁻¹⁹

= 480 x 10⁻¹⁹ N .

7 0

3 years ago

A pair of in-phase stereo speakers is placed side by side, 0.764 m apart. You stand directly in front of one of the speakers, 2.

Goryan [66]

Answer:

f = 2858.33 Hz

Explanation:

given,

distance between speaker (A) and the person = 2.34 m

Distance between speaker (B) and the person is AB =

= $\sqrt{(0.764)^2 + (2.34)^2}$

= 2.46 m

path difference d = BP - AP

= 2.46 - 2.34 m

= 0.12 m

now, λ = 0.12

speed of sound = 343 m/s

$f= \dfrac{c}{\lambda}$

$f= \dfrac{343}{0.12}$

f = 2858.33 Hz

the lowest frequency that will produce constructive interference is equal to

f = 2858.33 Hz

7 0

2 years ago

Is hydrogen balloon element mixture or compound

andrezito [222]

Answer:

compound

Explanation:

5 0

2 years ago