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Iteru [2.4K]
3 years ago
6

A starship blasts past the earth at 2.0*10^8 m/s .Just after passing the earth, the starship fires a laser beam out its back of

the starship.With what speed does the laser beam approach the earth?Express your answer using two significant figures.
Physics
1 answer:
Vilka [71]3 years ago
7 0

Answer:

at the speed of light (c=3.0\cdot 10^8 m/s)

Explanation:

The second postulate of the theory of the special relativity from Einstein states that:

"The speed of light in free space has the same value c in all inertial frames of reference, where c=3.0\cdot 10^8 m/s"

This means that it doesn't matter if the observer is moving or not relative to the source of ligth: he will always observe light moving at the same speed, c.

In this problem, we have a starship emitting a laser beam (which is an electromagnetic wave, so it travels at the speed of light). The startship is moving relative to the Earth with a speed of 2.0*10^8 m/s: however, this is irrelevant for the exercise, because according to the postulate we mentioned above, an observer on Earth will observe the laser beam approaching Earth with a speed of c=3.0\cdot 10^8 m/s.

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Compare two processes we use to measure the age of Earth and its parts.
yan [13]

Answer:

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Based on the research done by scientists, the Geologic Column, a graph that illustrates earth age, was developed. The Column, with its names for the epochs and eras of time, illustrates what scientists think was taking place in earth history. A small version of the Geologic Column is pictured at the right.

Explanation:

I hope this helps :)

3 0
3 years ago
Walking across a carpet is an example of charge being transferred by
Sati [7]

static electricity and friction

8 0
3 years ago
A motorbike accelerates from 15m/s to 25m/s in 15 seconds.
RSB [31]

distance traveled by a uniformly accelerated bike is given as

d = \frac{v_f + v_i}{2} (t)

here we know that

v_f = 25 m/s

v_i = 15 m/s

t = 15 s

now we will have from above equation

d = \frac{15 + 25}{2} (15)

d = 20 (15) = 300 m

so it will cover the total distance of 300 m

5 0
3 years ago
The solid rod shown has a radius of 0.75 in. if it is subjected to the force the 500lb determine the max normal stress developed
Kipish [7]
The normal stress follows the formula written below:

σ = F/A

There are two types of stress, axial and tangential. Since we are only given with the dimension of the radius (and not the length), the possible stress is axial. So, the area is,

A = πr² = π(0.75 in)² = 1.767 in²

So,
σ = F/A = 500 lb/1.767 in² = <em>282.94 psi</em>
7 0
3 years ago
PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!
Serhud [2]
True,
Explanation: because it’s the same reason that lighting touches the ground/ goes up to the sky, because it is trying to balance out its charges
4 0
3 years ago
Read 2 more answers
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