Which of the following does not contribute to the potential energy of an object?

The vectors of the magnetic field around a long, straight, current-carrying wire are:

Ksenya-84 [330]

Divide the long wire in small segments. The field due to one segment can be found from Biot- Savart law.

dB=(uo/4pi) Idlxr/r^3. In this expression if we take vector r perpendicular to current element , the cross product in the expression shows that the direction of B is perpendicular to vector r and from symmetry it can be said that field line is circular around the wire segment. This is true for all segment ,because in infinitely long wire all segments are equivalent . Thus, magnetic field lines are concentric around a long straight wire.

Hope it helps

3 0

4 years ago

Read 2 more answers

3. A girl is running the 200 m dash. She starts by acceleration at 8m/s^2 for 7s. Then continues at this speed until the end of

antoniya [11.8K]

Answer:

10.6 s

Explanation:

Given that a girl is running the 200 m dash. She starts by acceleration at 8m/s^2 for 7s. Then continues at this speed until the end of the race. How long did it take for her to complete the race?

Solution.

If she accelerated for 7s, the velocity at which she accelerated will be:

Acceleration = velocity/time

8 = V/7

Make V the subject of the formula by cross multiplying.

V = 8 × 7

V = 56 m/s

She maintains the speed through out the journey.

Speed = distance/time

Make time the subject of formula

Time = distance/speed

Time = 200 / 56

Time = 3.57s

Therefore, she will complete the race by 7 + 3.6 = 10.6 s

7 0

3 years ago

A street light is at the top of a 19 foot tall pole. A woman 5.25 feet tall walks towards the pole with a speed of 7ft/sec along

bezimeni [28]

Answer:

The tip of her shadow is moving at the speed of 9.66 ft/sec

Explanation:

The height of the street light = 19 feet

The height of the woman = 5.25 feet

Distance between the woman and the base of the pole, x = 35 ft

The speed of the woman towards the pole, dx/dt = 7ft/sec

The distance from the base of the streetlight to the tip of the woman's shadow = y

The distance from the woman to the tip of her shadow = y - x

The diagram illustrating this description is shown below

Using similar triangle:

$\begin{gathered} \frac{19}{5.25}=\text{ }\frac{y}{y-x} \\ 19(y-x)\text{ = 5.25y} \\ 19y-19x\text{ = 5.25y} \\ 19y-5.25y\text{ = 19x} \\ 13.75y\text{ = 19x} \\ y\text{ = }\frac{19}{13.75}x \\ y\text{ = }1.38x \end{gathered}$

Find the derivative of both sides with respect to time, t

$\begin{gathered} \frac{dy}{dt}=\text{ 1.38}\frac{dx}{dt} \\ \frac{dy}{dt}=\text{ 1.38(7)} \\ \frac{dy}{dt}\text{ = }9.66\text{ ft/sec} \end{gathered}$

The tip of her shadow is moving at the speed of 9.66 ft/sec

7 0

1 year ago

Balance the equation: ___ SiO2 + ___ HF  ___ SiF4 + ___ H2O

olga_2 [115]

Let's start from the Fluorine (F), which has 4 atoms on the right side: this means we must put a factor 4 in front of HF to balance the number of atoms of Fluorine.
Nowe we have 4 atoms of hydrogen, H, on the left side. Since we have a $H_2$ on the right side (2 atoms), we must put a factor 2 in front of $H_2 O$ , to balance the number of atoms of hydrogen.
So now the atoms of oxygen are also balanced (2 on both sides), as well as the atoms of Silicon (Si), so the balanced reaction is

$Si O_2 + 4 HF \rightarrow SiF_4 + 2 H_2 O$

3 0

3 years ago

4.

Ulleksa [173]

The correct answer is C. Universal Gravitation (it was written by Issac Newton)

4 0

4 years ago