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castortr0y [4]
3 years ago
8

Imagine that the light you observe from space is exhibiting a redshift. This would mean that the Universe is Choose one: A. trav

eling faster than the speed of light. B. traveling slower than the speed of sound. C. expanding. D. collapsing.
Physics
1 answer:
docker41 [41]3 years ago
7 0

Answer: C. Expanding

Explanation:

When an object moves away from an observer, the light waves emitted by the object are stretched out making them have move towards the red end of the electromagnetic spectrum, where light has a longer wavelength. This phenomenon is known as the redshift (cosmological redshift). For most astronomical objects, the observed spectral lines are all shifted to longer wavelengths. It is caused solely by the expansion of the Universe and thus, the value of a redshift indicates the recession velocity of the expanding object, or its distance.

Redshift is opposed to the blueshift. Blue light wavelengths tend to be closer together hence blueshift light tends to be emitted from objects that are collapsing.

You might be interested in
Suppose we measure the energy stored in some inductor to be E when there is a current I running through it. If I double the curr
slavikrds [6]

Answer:

If I double the current in the inductor, the new total energy will become 4E (option f).

Explanation:

The coil or inductor is a passive component made of an insulated wire that stores energy in the form of a magnetic field due to its form of coiled turns of wire, through a phenomenon called self-induction. In other words, inductors store energy in the form of a magnetic field. The energy stored in the space where there is a magnetic field in the inductor is:

E=\frac{1}{2} *L*I^{2}

where E is Energy [J], L is Inductance [H] and I is Current [A].

If you double the current in the inductor, then the new value of the current is I'= 2*I. So replacing the new total energy is:

E'=\frac{1}{2} *L*I'^{2}=\frac{1}{2} *L*(2*I)^{2}=\frac{1}{2} *L*4*I^{2}=4*\frac{1}{2} *L*I^{2}

Then:

E'=4*E

<em><u>If I double the current in the inductor, the new total energy will become 4E (option f).</u></em>

3 0
3 years ago
Now let’s apply the work–energy theorem to a more complex, multistep problem. In a pile driver, a steel hammerhead with mass 200
andrew11 [14]

Answer:

a) v = 7.67

b) n = 81562 N

Explanation:

Given:-

- The mass of hammer-head, m = 200 kg

- The height at from which hammer head drops, s12 = 3.00 m

- The amount of distance the I-beam is hammered, s23 = 7.40 cm

- The resistive force by contact of hammer-head and I-beam, F = 60.0 N

Find:-

(a) the speed of the hammerhead just as it hits the I-beam and

(b) the average force the hammerhead exerts on the I-beam.

Solution:-

- We will consider the hammer head as our system and apply the conservation of energy principle because during the journey of hammer-head up till just before it hits the I-beam there are no external forces acting on the system:

                                   ΔK.E = ΔP.E

                                  K_2 - K_1 = P_1- P_2

Where,  K_2: Kinetic energy of hammer head as it hits the I-beam

             K_1: Initial kinetic energy of hammer head ( = 0 ) ... rest

             P_2: Gravitational potential energy of hammer head as it hits the I-beam. (Datum = 0)

             P_1: Initial gravitational potential energy of hammer head      

- The expression simplifies to:

                                K_2 = P_1

Where,                     0.5*m*v2^2 = m*g*s12

                                v2 = √(2*g*s12) = √(2*9.81*3)

                                v2 = 7.67 m/s

- For the complete journey we see that there are fictitious force due to contact between hammer-head and I-beam the system is no longer conserved. All the kinetic energy is used to drive the I-beam down by distance s23. We will apply work energy principle on the system:

                               Wnet = ( P_3 - P_1 ) + W_friction

                               Wnet = m*g*s13 + F*s23

                               n*s23 = m*g*s13 + F*s23

Where,    n: average force the hammerhead exerts on the I-beam.

               s13 = s12 + s23

Hence,

                             n = m*g*( s12/s23 + 1) + F

                             n = 200*9.81*(3/0.074 + 1) + 60

                             n = 81562 N

                               

                                                   

6 0
3 years ago
A 5 kg block is pushed across a table by a horizontal force of 40 N with an acceleration of 5 m/s^2. What is the frictional forc
julsineya [31]

Answer:

15

Explanation:

mass, M = 5Kg

horizontal force, F_h = 40N

acceleration, a =5 m/s^2

frictional force, F_f =?

net force = ma

net force = F_h - F_f = 40N - F_f

40  - F_f = 5 x 5

- F_f = 25 - 40

multiply both side by -1

F_f = 40 - 25 = 15

the frictional force is 15N

4 0
3 years ago
An object of mass 'm' is on an inclined plane with an
Levart [38]

Answer:

F_{\text{par}} = F_{\text{frict}}

F_{\text{norm}} = F_{\text{perp}}

Explanation:

See attachment for complete work.

Download pdf
7 0
2 years ago
What is the energy due to compressing a spring
Westkost [7]

Answer: Elastic Potential Energy

Explanation: Energy present on compressed strings is called Elastic Potential Energy.

8 0
3 years ago
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