If a car has a velocity of 40 km/h west and then comes to a stop in 5 s, what is its acceleration in m/s2?

When blueshift occurs,the preceived frequency of the wave would be?

LiRa [457]

Answer:

When blueshift happens, the perceived frequency of the wave would be higher than the actual frequency.

Explanation:

As the name suggests, when blueshift happens to electromagnetic waves, the frequency of the observed wave would shift towards the blue (high-frequency) end of the visible spectrum. Hence, there would be an increase to the apparent frequency of the wave.

Blueshifts happens when the source of the wave and the observer are moving closer towards one another.

Assume that the wave is of frequency $f\; {\rm Hz}$ at the source. In other words, the source of the wave sends out a peak after every $(1/f)\; {\text{seconds}}$ .

Assume that the distance between the observer and the source of the wave is fixed. It would then take a fixed amount of time for each peak from the source to reach the observer.

The source of this wave sends out a peak after each period of $(1/f)\; {\text{seconds}}$ . It would appear to the observer that consecutive peaks arrive every $(1/f)\; {\text{seconds}}\!$ . That would correspond to a frequency of $f\; {\rm Hz}$ .

On the other hand, for a blueshift to be observed, the source of the wave needs to move towards the observer. Assume that the two are moving towards one another at a constant speed of $v \; {\rm m \cdot s^{-1}}$ .

Again, the source of this wave would send out a peak after each period of $(1/f)\; {\text{seconds}}$ . However, by the time the source sends out the second peak, the source would have been $v \cdot (1 / f) \; { \rm m}= (v / f)\; {\rm m}$ closer to the observer then when the source sent out the first peak.

When compared to the first peak, the second peak would need to travel a slightly shorter distance before it reach the observer. Hence, from the perspective of the observer, the time difference between the first and the second peak would be shorter than $(1/f)\; {\text{seconds}}$ . The observed frequency of this wave would be larger than the original $f\; {\rm Hz}$ .

6 0

3 years ago

If released, the chemical potential energy will cause the coal atoms and molecules to vibrate violently, and this internal kinet

nata0808 [166]

Answer:

A. burn the coal

Explanation:

Burning the coal is only the way to convert the stored chemical energy of the coal into the the kinetic energy of its molecules that can then be transferred to the nearby objects in the form of heat by the various modes of heat transfer such as conduction, convection or radiation.

Conduction is the contact method of heat transfer in which the adjacent atom transfers the vibration kinetic energy.

Convection is the bulk mode of heat transfer in which the bulk mass of molecules moves near and far to the heat source.

Radiation is the distant mode of heat transfer in the form of electromagnetic waves.

5 0

3 years ago

Read 2 more answers

Light in the air is incident at an angle to the surface of (12.0 A) degrees on a piece of glass with an index of refraction of (

Orlov [11]

The question is incomplete. You dis not provide values for A and B. Here is the complete question

Light in the air is incident at an angle to a surface of (12.0 + A) degrees on a piece of glass with an index of refraction of (1.10 + (B/100)). What is the angle between the surface and the light ray once in the glass? Give your answer in degrees and rounded to three significant figures.

A = 12

B = 18

Answer:

18.5⁰

Explanation:

Angle of incidence i = 12.0 + A

A = 12

= 12.0 + 12

= 14

Refractive index u = 1.10 + B/100

= 1.10 + 18/100

= 1.10 + 0.18

= 1.28

We then find the angle of refraction index u

u = sine i / sin r

u = sine24/sinr

1.28 = sine 24 / sine r

1.28Sine r = sin24

1.28 sine r = 0.4067

Sine r = 0.4067/1.28

r = sine^-1(0.317)

r = 18.481

= 18.5⁰

4 0

3 years ago

Help on matching please, struggling on it. Even just 1 or 2 would help

n200080 [17]

Answer:

7. free fall -- h. 9.8m/s^2

3. Velocity -- x. 60 km/hr west

6. Acceleration -- d. change in velocity/time

8. Centrifugal -- s. towards the centre

13. Work done --w. Force * displacement

5. Uniform circular motion --j. spin cycle in washer

18. Power -- r. kW an hour

7. g -- a. 10N

hope this helps

6 0

3 years ago

Why is honesty especially important in a scientist when the results of an experiment go against predictions❓❔

kramer

Because other scientists and science in general rely on their collegues' research which in turn allows development of our knowledge on the given subject. The more dont-to-earth reason may be safety. If someone performs an experiment without knowledge of its true results it might result in some danger to the safety of those perforning it without knowledge of all the risks.

8 0

3 years ago