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agasfer [191]
3 years ago
14

A car advertisement states that a certain car that emily miller loves can accelerate from rest to 70 km/h in 7 seconds. Find the

cars average acceleration
Physics
1 answer:
nalin [4]3 years ago
3 0
Kinematics equations are vital for this:

v_0(initial velocity)           v_f(final velocity)     a(acceleration)

v_0=70 km/h    v_f= 0 km/h( rest)

Kinematics equation is a=(v_f-v-0)/time
a=(0-70)/(7/3600)  which means it decelerates at -36000 km/h

This number is humongous; I would advise you to re-check the problem and see if the the time it takes is 7 hours rather than 7 seconds. Notice that I put the time as 7/3600 because it is 7 seconds which should be converted to hours.
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A student throws a set of keys vertically upward to his fraternity brother, who is in a window 3.60 m above. The brother's outst
Contact [7]

Answer:

v_{i}=10.10 m/s

Explanation:

The equation of the position is:

y=y_{i}+v_{i}t-0.5gt^{2}

Where:

v(i) is the initial velocity

The initial position y(i) will be zero and the final position y = 3.60 m.

So, we just need to solve this equation for v(i).

v_{i}=\frac{y+0.5gt^{2}}{t}

v_{i}=\frac{3.6+0.5*9.81*1.6^{2}}{1.6}

v_{i}=10.10 m/s

Therefore, the initial velocity is 10.10 m/s upwards.

I hope it helps you!

5 0
3 years ago
Explain how this increases their efficiency. Explain how this increases their efficiency. Antireflective coating causes the phas
sweet [91]

Answer:

c) True. If the coating cancels the light requested by the reflection, so there is more energy to enter the cell and therefore its efficiency increases

Explanation:

This exercise asks to analyze the effect of the antireflective coating on the efficiency of solar cells.

Let's start by expressing the expression for the interference of two light beams taken at when

* the phase change introduced when passing from air to 180º film

* the wavelength change by the refractive index of the film ln = lo / n

therefore the expression for destructive interference is

            2 n t = m λ

where m is an integer

with these concepts we can analyze the different statements

a) False. Phase shift does not change the wavelength of light

b) False. The refractive index of the solar cell is not affected by the refractive index of the film since the two materials do not mix.

c) True. If the coating cancels the light requested by the reflection, so there is more energy to enter the cell and therefore its efficiency increases

d) false. In solar cells the incidence is almost normal, therefore the effect of refraction (separation of colors for different angles) is very small

7 0
3 years ago
Two sources emit beams of light of wavelength 550 nm. The light from source A has an intensity of 10 μW/m2, and the light from s
alexira [117]

Answer:

<em>A) Beam B carries twice as many photons per second as beam A.</em>

Explanation:

If we have two waves with the same wavelength, then their intensity is proportional to their power, or the energy per unit time.

We also know that the amount of photon present in an electromagnetic beam is proportional to the energy of the beam, hence the amount of beam per second is proportional to the power.

With these two facts, we can say that the intensity is a measure of the amount of photon per second in an electromagnetic beam. So we can say that <em>beam B carries twice as more power than beam A, or Beam B carries twice as many photons per second as beam A.</em>

3 0
3 years ago
2. **A bird is flying south for the winter and mies a total o
dimulka [17.4K]

Answer:

Explanation:

By definition we get that,

velocity = displacement change/ time taken

So for bird we can use,

velocity of the bird = displacement change/ time taken

= 8000/4 = 2000 miles per day =326.61 m/s

3 0
3 years ago
Write 1,2,3 to order how a plants become part of soil.:-the plant breaks down into bits./ a dead plants fall to the ground./ the
ExtremeBDS [4]
1. The plant breaks down into bits
2. A dead plant falles to the ground
3 The bits become part of soil
6 0
3 years ago
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