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1 year ago

Pls help I’m in a middle of a test and I can’t find the answer

Physics

2 answers:

EastWind [94]1 year ago

5 0

Answer:

I believe the answer is B.

Aloiza [94]1 year ago

3 0

Answer: B

Explanation: This seems like the most logical answer out of the given choices.

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(b) Figure 3.32 shows the orbit of a planet around the Sun. Compare the linear speed of the planet at positions X, Y and Z.

Viefleur [7K]

At Z ... slowest speed

At Y ... fastest speed

At X ... medium speed

Wherever it is in its orbit, the line from the planet to the Sun smears over the same amount of area every second.

That's Kepler's second law of planetary motion.

The reason this happens is: That's how gravity works. (A better explanation is available, but first you have to be able to twirl calculus and solid geometry in the air on long sticks.)

5 0

3 years ago

Suppose a soccer player kicks the ball from a distance 29 m toward the goal. find the initial speed of the ball if it just passe

Rudik [331]

The ball's vertical velocity at the time it just passes over the goal is 0 m/s. Its initial vertical velocity is unknown and we denote it by $v\sin39^\circ$ , where $v$ here is the ball's initial speed. Vertically, the only force acting on the ball is gravity, which attributes a downward acceleration of 9.8 m/s^2. We expect the maximum height achieved by the ball to be 2.4 m, so we can find the initial speed by solving

$\left(0\,\dfrac{\mathrm m}{\mathrm s}\right)^2-\left(v\sin39^\circ\right)^2=2\left(-9.8\,\dfrac{\mathrm m}{\mathrm s^2}\right)(2.4\,\mathrm m)$

$\implies v=11\,\dfrac{\mathrm m}{\mathrm s}$

6 0

3 years ago

At locations A and B, the electric potential has the values VA=1.51 VVA=1.51 V and VB=5.81 V,VB=5.81 V, respectively. A proton r

Oksana_A [137]

Answer:

For proton:

A. The proton is released from Vb (highest potential)

B. v = 2.9x10⁴ m/s

For electron:

A. The electron is released from Va (lowest potential)

B. v = 1.2x10⁶ m/s

Explanation:

For a proton we have:

A. To find the origin from which the proton was released we need to remember that in a potential difference, a proton moves from the highest potential to the lowest potential.

Having that:

Va = 1.51 V and Vb = 5.81 V

We can see that the proton moves from Vb to Va, hence the proton was released from Vb.

B. We now that the work done by an electric field is given by:

$W = \Delta Vq$ (1)

Where:

q: is the proton's charge = 1.6x10⁻¹⁹ C

V: is the potential

Also, the work is equal to:

$W = \Delta K = (K_{a} - K_{b}) = \frac{1}{2}mv_{a}^{2} - \frac{1}{2}mv_{b}^{2}$ (2)

Where:

K: is the kinetic energy

m: is the proton's mass = 1.67x10⁻²⁷ kg

$v_{a}$ : is the velocity in the point a

$v_{b}$ : is the velocity in the point b = 0 (starts from rest)

Matching equation (1) with (2) we have:

$\Delta Vq = \frac{1}{2}mv_{a}^{2}$

$(5.81 V - 1.51 V)*1.6 \cdot 10^{-19} C = \frac{1}{2}1.67 \cdot 10^{-27} kg*v_{a}^{2}$

$v_{a} = 2.9 \cdot 10^{4} m/s$

For an electron we have:

A. For an electron we know that it moves from the lowest potential (Va) to the highest potential (Vb), so it is released from Va.

B. The speed is:

$\Delta Vq = \frac{1}{2}mv_{b}^{2} - \frac{1}{2}mv_{a}^{2}$

Since $v_{a}$ = 0 (starts from rest) and $m_{e}$ = 9.1x10⁻³¹ kg (electron's mass), we have:

$(5.81 V - 1.51 V)*1.6 \cdot 10^{-19} C = \frac{1}{2}9.1 \cdot 10^{-31} kg*v_{b}^{2}$

$v_{b} = 1.2 \cdot 10^{6} m/s$

I hope it helps you!

6 0

4 years ago

The energy per unit volume in an electromagnetic wave is: ________

Marianna [84]

Answer:

Explanation:

Electromagnetic waves are waves that are generated when an electric field and a magnetic field vibrate together. They are usually created whenever an electric field collides with a magnetic field.

In more generic terms for an electric field, the energy per unit volume is given by:

Energy density = $\dfrac{1}{2}\varepsilon _oE^2$

For magnetic field:

Energy density = $\dfrac{\beta^2}{2 \mu _o}$

∴

For the electromagnetic wave (u):

Total energy density is:

$u = \dfrac{1}{2}\varepsilon_oE^2 + \dfrac{\beta ^2}{2 \mu_o}$

Due to the fact that the energy related with both fields is equivalent:

Then:

E = cB

6 0

3 years ago

Is vibrating considered work

allsm [11]

Answer: no it shouldn't be

Explanation:

8 0

3 years ago