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svetoff [14.1K]
4 years ago
11

It is necessary to develop alternative sources of energy because _____.

Physics
1 answer:
Leona [35]4 years ago
3 0
Because we wish to have a sustainable future. The current dependence on fossil fuel means that there will be a point when humans have no fuel to use because fossil fuels are a non-renewable resource.
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Suppose that A’, B’ and C’ are at rest in frame S’, which moves with respect to S at speed v in the +x direction. Let B’ be loca
Inga [223]

Answer:

1) an observer in B 'sees the two simultaneous events

2)observer B sees that the events are not simultaneous

3)  Δt = Δt₀ /√ (1 + v²/c²)

Explanation:

This is an exercise in simultaneity in special relativity. Let us remember that the speed of light is the same in all inertial systems

1) The events are at rest in the reference system S ', so as they advance at the speed of light which is constant, so it takes them the same time to arrive at the observation point B' which is at the point middle of the two events

Consequently an observer in B 'sees the two simultaneous events

2) For an observer B in system S that is fixed on the Earth, see that the event in A and B occur at the same instant, but the event in A must travel a smaller distance and the event in B must travel a greater distance since the system S 'moves with velocity + v. Therefore, since the velocity is constant, the event that travels the shortest distance is seen first.

Consequently observer B sees that the events are not simultaneous

3) let's calculate the times for each event

        Δt = Δt₀ /√ (1 + v²/c²)

where t₀ is the time in the system S' which is at rest for the events

8 0
3 years ago
Two uncharged metal spheres, #1 and #2, are mounted on insulating support rods. A third metal sphere, carrying a positive charge
tatuchka [14]

Answer:

The question is incomplete as some details are missing, here is the details ;

In this final state

a) spheres #1 and #2 both carry negative charge.

b) sphere #1 carries negative charge and #2 carries positive charge.

c) spheres #1 and #2 are still uncharged.

d) sphere #1 carries positive charge and #2 carries negative charge.

e) spheres #1 and #2 both carry positive charge.

Explanation:

From the concept of electrostatics, if a positively charged sphere is brought close to #2, there will be attraction of the opposite charges(-ve) towards it.

Now connecting a copper wire between #1 and #2, opposite charges will flow from #1 towards #2. disconnecting the copper wire makes #1 to be positively charged and #2 to be negatively charge and from the laws of attraction ; Like charges repel and unlike charges attract. the correct option is d.

5 0
3 years ago
9) Manypeoplearefamiliarwiththefactthatariflerecoilswhenfired.Thisrecoilistheresultof actionreactionforcepairs.Agunpowderexplosi
ycow [4]

Answer:

B. Smaller than the acceleration of the bullet.

Explanation:

According to the law of  conservation of momentum; the total momentum of the gun and bullet after firing is equal to the total momentum of the gun and bullet before firing.

However, the mass of gun is much larger than that of the bullet hence it follows that the velocity and acceleration during the recoil of the rifle is much smaller in comparison to the velocity and acceleration of the of bullet.

So; the acceleration of the rifle is given by the force exerted on the rife by the bullet divided by the mass of the rifle. Given that the mass of the rifle is much greater than the mass of the bullet, the acceleration of the rifle is much less than that of the bullet.

6 0
3 years ago
And air rifle pellet of mass 2 g Is fired into a block of modelling clay mounted on a model railway track. The trunk and modelli
Anna007 [38]

Answer:

0.0816 kgm/s

Explanation:

From the question,

Momentum of the pellet just before it hits the modelling clay is = (mass of the pellet+ mass of the truck clay)×initial velocity of pellet.

P =(M+m)u...................... Equation 1

Where P =  initial momentum of the pellet, m = mass of the pellet, u = initial speed of the pillet, M = mass of the truck

Given: m = 2 g = 2/1000 kg = 0.002 kg, u = 0.8 m/s, M = 0.1 kg

Substitute these values into equation 1

P = (0.002+0.1)0.8

P = (0.102)0.8

P = 0.0816 kgm/s

4 0
3 years ago
Why is it important to have the international system of units?
Roman55 [17]
It is important to have the international system of units 'cause <span>it can be used by scientists everywhere around the world, and they will be able to understand each other with more accuracy.

In short, Your Answer would be Option D

Hope this helps!</span>
8 0
3 years ago
Read 2 more answers
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