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3 years ago

Use the velocity vs time graph to analyze the motion of the object.

Physics

1 answer:

arsen [322]3 years ago

7 0

Explanation:

the object has constant velocity for 2 seconds and it get a constant accelration (2ms-2)

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If the diameter of a radar dish is doubled, what happens to its resolving power assuming that all other factors remain unchanged

kirill115 [55]

Answer:

θ’ = θ₀ / 2

we see that the resolution angle is reduced by half

Explanation:

The resolving power of a radar is given by diffraction, for which we will use the Rayleigh criterion for the resolution of two point sources, they are considered resolved if the maximum of diffraction of one coincides with the first minimum of the other.

The first minimum occurs for m = 1, so the diffraction equation of a slit remains

a sin θ = λ

in general, the diffraction patterns occur at very small angles, so

sin θ = θ

θ = λ / a

in the case of radar we have a circular aperture and the equation must be solved in polar coordinates, which introduces a numerical constant.

θ = 1.22 λ /a

In this exercise we are told that the opening changes

a’ = 2 a

we substitute

θ ‘= 1.22 λ / 2a

θ' = (1.22 λ / a) 1/2

θ’ = θ₀ / 2

we see that the resolution angle is reduced by half

8 0

3 years ago

When an electron falls from a higher to a lower energy level in an atom, the photon released has a wavelength of 121.6 nm. What

yarga [219]

Answer:

$\Delta E=1.64*10^{-18}J$

Explanation:

The energy difference between the energy levels involved in the transition of the electron is directly proportional to the frequency of the emitted photon:

$\Delta E=h\nu(1)$

Where h is the Planck constant. The photon's frequency is inversely proportional to its wavelegth:

$\nu=\frac{c}{\lambda}(2)$

Here c is the speed of light. Replacing (2) in (1):

$\Delta E=\frac{hc}{\lambda}\\\Delta E=\frac{(6.63*10^{-34}J\cdot s)(3*10^8\frac{m}{s})}{121.6*10^{-9}m}\\\Delta E=1.64*10^{-18}J$

6 0

3 years ago

How can i stop loveing you if yo keep saying the things i want to hear

xxTIMURxx [149]

Answer:

....

Explanation:

5 0

2 years ago

Read 2 more answers

A heat pump has a coefficient of performance that is 60% of the Carnot heat pump coefficient of performance. The heat pump is us

Nataliya [291]

Answer:

$T_C$ =118.8 K= 154.2°C

Explanation:

COP_max of carnot heat pump= $\frac{T_{H} }{T_{H}-T_{C} }$

where T_H and T_C are temperatures of hot and cold reservoirs

Also COP= $\frac{Q_H}{W}$

in the question $COP= \frac{60}{100} \times COP_{max}$

⇒ $\frac{Q_H}{W} =\frac{60}{100}\times\frac{T_H}{T_H-T_C}$

heat is added directly to be as efficient as via heat pump

$Q_H= W$

and T_H= 24° C= 297 K

$1=\frac{60}{100}\times \frac{297}{297-T_C}$

on calculating the above equation we get

$T_C$ =118.8 K

the outdoor temperature for efficient addition of heat to interior of home

$T_C$ =118.8 K= 154.2°C

6 0

3 years ago

Two spacecraft are both 10 million kilometers from a star. The total power output of the star is 4 x 1025 W. Spacecraft 1 has a

Ksenya-84 [330]

The concept of power is given by the relationship between intensity and area, that is to say that power is defined as

$P = A*I$

Our values are given under the condition of,

$r_1 = 18m$

$r_2 = m$

The power is proportional to the Area, and in turn, we know that the Area of a circle is the product between $\pi$ times the radius squared, therefore the power is proportional to the radius squared.

$\text{Power} \propto r^2$

For both panels we would have to

$\frac{\text{Power by panel 1}}{\text{Power by panel 2}} = \frac{r_1^2}{r_2^2}$

$\frac{P_1}{P_2} = (\frac{18}{6})^2$

$\frac{P_1}{P_2} = 9$

Therefore the correct option is option C.9

5 0

3 years ago

Read 2 more answers