Explanation:
In train's rest frame, the speed of photon is and the proper length of the train is . The time taken by the photon to cross the train is
In ground frame, the speed of the photon is given as follows:
The speed of light or photon remains same in every frame of reference.
Now, the speed of train is very less as compared to the speed of photon so that So that,
The length contraction in the ground frame is given as follows:
Time taken by the photon to travel the length of the train in ground frame is .
Answer:
a.They have a smaller proportion of heavy elements.
Explanation:
As a star grows old , its metal content becomes low . Our sun is Population I star which means it is very new . Its metal content is 1.4 % . By the term metal we mean any element heavier than helium . Population II stars are older than population I stars . They will have lesser content of metal . Population III are oldest star group which have metal content as less as .015 % .
Answer:
<em>I think the answer is C</em>
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Explanation:
Its heavy but not too heavy
Work = force x distance. In units, Joules = Newtons x meters.
So: Work = 50 Newtons x 3 meters
Work = 150 joules. Answer D is correct
FYI - to ace physics, you should learn to identify these values using their fundamental units:
Force = Newtons = Kg·m/s²
Work = joules = kg·m²/s²
Power = watts = kg·m²/s³
In high school physics, If you learn to arrange equations so the units work out properly for the answer, you'll get most problems correct.
Answer:
98.1 Joule
Explanation:
Solution,
⇒Mass(m)=10kg
⇒Weight(F)=Mg=10×9.81=98.1N
⇒Distance(d)=1m
Now,
Work done=F×d
=98.1×1
=98.1J