Suppose a logs mass is 5kg .after burning,the mass of the ash is 1kg .explain what may have happened to the other 4kg
1 answer:
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Answer: 25.38 m/s
Explanation:
We have a straight line where the car travels a total distance , which is divided into two segments
:
(1)
Where
On the other hand, we know speed is defined as:
(2)
Where is the time, which can be isolated from (2):
(3)
Now, for the first segment the car has a speed
, using equation (3):
(4)
(5)
(6) This is the time it takes to travel the first segment
For the second segment the car has a speed
, hence:
(7)
(8)
(9) This is the time it takes to travel the secons segment
Having these values we can calculate the car's average speed :
(10)
(11)
Finally:
Answer:
at the speed of light ()
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 "
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 .