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2 years ago

NEED HELP ASAP!!!!!!!!!!

Physics

1 answer:

stepan [7]2 years ago

3 0

Answer:

*The same balloon put into the freezer would be smaller and shriveled.

* The volume decreases as the temperature decreases.

* using a hypothetical starting volume of 2 liters in the balloon at 42 degrees Celsius, we can use the equation V1/T1 =V2/T2

V2= 1.54 liters which proves when temperature decreases , volume decreases as well.

Explanation:

The volume increases as the temperature increases, and volume decreases as the temperature decreases.

using a hypothetical starting volume of 2 liters in the balloon at 42 degrees Celsius, we can use the equation V1/T1 =V2/T2

Change Celsius to kelvin by adding 273.

2 liters/ 315 K = V2/243 K

Cross multiply and then divide by 315 to find V2

2 liters x 243 K / 315 K = V2

The Kelvin cancels itself out.

486 liters /315=V2

V2= 1.54 liters.

This proves that when the temperature decreases , so does the volume.

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We would round this to:

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3 years ago

If a 75 W lightbulb is 15% efficient, how many joules of light energy does the bulb produce every minute?

stiks02 [169]

Answer:

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2 years ago

Assume that the electric field E is equal to zero at a given point. Does it mean that the electric potential V must also be equa

lyudmila [28]

Answer:

No, this doesn't mean the electric potential equals zero.

Explanation:

In electrostatics, the electric field $\vec{E}$ is related to the gradient of the electric potential V with :

$\vec{E} (\vec{r}) = - \vec{\nabla} V (\vec{r})$

This means that for constant electric potential the electric field must be zero:

$V(\vec{r}) = k$

$\vec{E} (\vec{r}) = - \vec{\nabla} V (\vec{r}) = - \vec{\nabla} k$

$\vec{E} (\vec{r}) = - (\frac{\partial}{\partial x} , \frac{\partial}{\partial y } , \frac{\partial}{\partial z}) k$

$\vec{E} (\vec{r}) = - (\frac{\partial k}{\partial x} , \frac{\partial k}{\partial y } , \frac{\partial k}{\partial z})$

$\vec{E} (\vec{r}) = - (0,0,0)$

This is not the only case in which we would find an zero electric field, as, any scalar field with gradient zero will give an zero electric field. For example:

$V(\vec{r})= (x+2)^2 (y+4)^3 (z+5)^4$

give an electric field of zero at point (0,0,0)

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3 years ago

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2 years ago

Jin knows that the initial internal energy of a closed system is 78 J and the final internal energy is 180 J. He also knows that

lawyer [7]

As we know by the first law of thermodynamics

$Q = \Delta U + W$

here we know that

Q = heat given to the system

$\Delta U = U_f - U_i$

W = work done by the system

now here we can say

$\Delta U = 180 - 78 = 102 J$

$W = 64 J$

now we can say that heat will be given as

$Q = 64 + 102 = 166 J$

now here we can say that Jin does the error in his first step while calculation of change in internal energy as he had to subtract it while he added the two energy

So best describe Jin's Error is

<em>B )For step 1, he should have subtracted 78 J from 180 J to find the change in internal energy. </em>

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3 years ago