Answer: Option B: They don't understand how redshifts affects stars.
There are millions and billions of stars in our universe. Scientists study stars using telescopes. But some stars are so far, that even the best powerful telescopes are not able to detect their light. Also, the interstellar distance is filled with clouds of dust and gas which makes some part of the universe opaque. It becomes difficult to study stars using earth based telescopes due to lot of light pollution. Astronomers understand how redshifts affects stars and hence, are able use this to study stars via their spectrum. Hence, astronomers don't understand how redshifts affects stars is a wrong reason of why they face difficulty in looking at distant stars.
Area because CM^2 is the unit used for Area
- Speed of the mobile = 250 m/s
- It starts decelerating at a rate of 3 m/s²
- Time travelled = 45s
- Velocity of mobile after 45 seconds
We can solve the above question using the three equations of motion which are:-
- v = u + at
- s = ut + 1/2 at²
- v² = u² + 2as
So, Here a is acceleration of the body, u is the initial velocity, v is the final velocity, t is the time taken and s is the displacement of the body.
We are provided with,
- u = 250 m/s
- a = -3 m/s²
- t = 45 s
By using 1st equation of motion,
⇛ v = u + at
⇛ v = 250 + (-3)45
⇛ v = 250 - 135 m/s
⇛ v = 115 m/s
✤ <u>Final</u><u> </u><u>velocity</u><u> </u><u>of</u><u> </u><u>mobile</u><u> </u><u>=</u><u> </u><u>1</u><u>1</u><u>5</u><u> </u><u>m</u><u>/</u><u>s</u>
<u>━━━━━━━━━━━━━━━━━━━━</u>
Taking a look at the image in the attachment, we discover that we can calculate the magnitude of the horizontal components using our knowledge of trigonometry. Since we are comparing the resultant and the horizontal component, the equation connecting them is
, where is the horizontal component, and is the resultant vector. Now we have to make
, and this is how we calculate the magnitude of the horizontal component.