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3 years ago

The worker in the picture is

1 answer:

7 0

It is C) doing work because he is moving the bale of cotton.It only makes sense he is still doing work the pulley is just making it easier.

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A 9.0-V battery moves 20 mC of charge through a circuit running from its positive terminal to its negative terminal. How much en

dem82 [27]

Answer:

E = 0.18 J

Explanation:

given,

Potential of the battery,V = 9 V

Charge on the circuit, Q = 20 m C

= 20 x 10⁻³ C

energy delivered in the circuit

E = Q V

E = 20 x 10⁻³ x 9

E = 180 x 10⁻³

E = 0.18 J

Energy delivered in the circuit is equal to E = 0.18 J

7 0

4 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)

8 0

4 years ago

Imagine a large block that sinks in a tub of water. You hold a much smaller block of the exact same material in your hand, above

goldenfox [79]

It will sink because mass does not affect the physical properties of the object.

3 0

4 years ago

Can someone help me on no. 6

liq [111]

Efficiency = (energy that does the job) / (total energy used)

= (45 J) / (120J)

I think you can handle the division.

8 0

3 years ago

Cindy runs 2 kilometers every morning. She takes 2 minutes for the first 250 meters, 4 minutes for the next 1,000 meters, 1 minu

Kobotan [32]

About 285 meters per minute

4 0

4 years ago

Read 2 more answers