### 10 Special Relativity Practice Questions and Answers

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Team **Space Chemistry** has summarized examples of special relativity problems and their solutions for students from various book publishers, totaling 10 items. In helping the quality of education in Indonesia, we always contribute so that students can learn and understand the calculation of questions related to material from the Theory of Relativity (Relativistic).

## 1 – 10 Special Relativity Questions and Answers

1. What is the speed of a rocket whose bell travels 1 second late in 1 hour relative to the bell on earth?

#### Solution

In this case t_{ο} = 3600s is the proper time interval on earth and t = 3601 s is the time interval in the moving frame. We solve as follows.

2. The distant galaxy in the constellation Hydra is moving away from Earth at a speed of 6.12 x 10^^{7}m/s, what is the shift in the green spectral line with a wavelength of 500nm emitted by this galaxy (towards the red of the spectrum)?

#### Solution

3. Find the mass of the electron me = 9.1×10^{-31}kg with a speed of 0.99c !

#### Solution

4. An object that is initially at rest suddenly explodes into two pieces, each with a mass of 2 kg and moving away from each other with a speed of 0.8c. Find the rest mass again!

#### Discussion

we calculate using the relativistic law of conservation of energy energi

initial energy = final energy

m₀.c² = m₀₁.c² + m₀₂.c²

we divide both sides by c², and

because the objects break with the same mass and the same velocity then:

m₀ = m₀₁ + m₀₂

m₀ = 2γm₀₁

for a speed of 0.8c then = 10/6

m₀ = 2.(10/6).(2)

= 40/6

= 6.67 kg

5. If the speed of light were less than c, would relativistic phenomena be easier to observe than they are now?

#### Discussion

Yes, because nothing exceeds the speed of light other than photons. The smaller the speed of an object than the speed of light, the easier it is to observe.

6. How fast is the spacecraft moving relative to the earth so that a day on the plane is equal to 2 seconds on earth?

#### Solution

7. Find the speed of the spacecraft whose bell goes 15 seconds slower per hour relative to the bell on earth!

#### Solution

8. A spacecraft moving away from Earth at a speed of 0.97c transmits data at a speed of 10^{4} pulses/second. at what rate is the data received?

#### Solution

9. Spectral lines whose wavelengths in the laboratory are 400 nm are shifted to 600 nm in the spectrum of a distant galaxy. What is the speed away from the galaxy?

#### Solution

10. An astronaut who is 6 ft high on the earth, lies parallel to the axis of a spacecraft moving with a speed of 0.9c relative to the earth. What is the height of the astronaut if measured by the observer in the plane!

#### Discussion