HELPPPP PLSSS I NEED HELP

A particular spectral line from an observed object is measured to be at a wavelength of 400 nm. that same spectral line is found

Butoxors [25]

To find the radial velocity of the object we are going to apply the regular Doppler formula:
[measured wavelenght - rest wavelenght/ rest wavelenght] = V/C, where V is the radial velocity and C is the speed of light which is equal to 300,000km/sec.
[400 - 800/800] = V/300,000 = - 150,000.
This means that the object is moving at a velocity of 150,000km/sec toward the observer.
The minus sign infront of the answer indicates that the object is moving towards the observer while a positive value will indicate that the object is moving away from the observer.

5 0

3 years ago

A 95 kg fullback is running at 3.0 m/s to the east and is stopped in 0.85 s by a head-on tackle by a tackler running due west. C

STatiana [176]

(a) Original momentum of the fullback: 285 kg m/s

The original momentum of the fullback is equal to the product between his velocity and its mass:

$p_i=mv$

where:

m = 95 kg is the mass

v = 3.0 m/s is the velocity

Substituting the numbers into the formula, we find

$p_i=(95 kg)(3.0 m/s)=285 kg m/s$

(b) Impulse exerted on the fullback: -285 kg m/s

The impulse exerted on the fullback is equal to his variation of momentum:

$I=\Delta p=p_f -p_i$

where:

$p_f = 0$ is the final momentum of the fullback (zero because he comes to a stop)

$p_i = 285 kg m/s$ is the initial momentum

Substituting,

$I=0-(285 kg m/s)=-285 kg m/s$

(c) Impulse exerted on the tackler: 285 kg m/s

The total momentum of the fullback and the tackler must be conserved:

$p_i + P_i = p_f + P_f$

where $p_i$ and $p_f$ are the initial and final momentum of the fullback, while $P_i, P_f$ are the initial and final momentum of the tackler.

We can re-arrange the equation as follows:

$P_f - P_i = p_i -p_f\\\Delta p_{tackler} = -\Delta p_{fullback}\\I_{tackler} = -I_{fullback}$

which means that the impulse exerted on the tackler is the negative of the impulse exerted on the fullback, so:

$I=-(-285 kg m/s)=285 kg m/s$

(d) Average force exerted on the tackler: 335.3 N

The impulse on the tackler is equal to the product between the average force and the time of the collision:

$I=F \Delta t$

Since $\Delta t=0.85 s$ , we can find the average force:

$F=\frac{I}{\Delta t}=\frac{285 kg m/s}{0.85 s}=335.3 N$

5 0

4 years ago

The Doppler effect is the actual change in a star’s frequency of a wave. True False

Akimi4 [234]

The answer of this question maybe false

6 0

3 years ago

Read 2 more answers

An inventor claims to have invented a heat engine that receives 750kJ of heat from a source at 400K and produces 250kJ of net wo

IRISSAK [1]

Answer:

the claim is not valid or reasonable.

Explanation:

In order to test the claim we will find the maximum and actual efficiencies. maximum efficiency of a heat engine can be found as:

η(max) = 1 - T₁/T₂

where,

η(max) = maximum efficiency = ?

T₁ = Sink Temperature = 300 K

T₂ = Source Temperature = 400 K

Therefore,

η(max) = 1 - 300 K/400 K

η(max) = 0.25 = 25%

Now, we calculate the actual frequency of the engine:

η = W/Q

where,

W = Net Work = 250 KJ

Q = Heat Received = 750 KJ

Therefore,

η = 250 KJ/750 KJ

η = 0.333 = 33.3 %

η > η(max)

The actual efficiency of a heat engine can never be greater than its Carnot efficiency or the maximum efficiency.

Therefore, the claim is not valid or reasonable.

3 0

3 years ago

If you were a lunar inhabitant what kinds of eclipses might you expect to see

MrRissso [65]

Hello
You expect to see:

1) A solar eclipse, when the earth is between the sun and the moon: the shadow of the earth is projected on the moon surface, and the sun will appear dark

2) An "earth eclipse", when the moon is between the sun and the earth: the shadow of the moon is projected on the earth surface, therefore the earth will appear dark.

5 0

3 years ago