The luminous star Alnilam in the Orion belt is 1,340 light-years away from Earth. Use the conversion factor 1 parsec = 3.262 lig
ht-years to find the closest conversion of this distance from light-years to parsecs (pc).
2 answers:
Answer:
The distance to the star Alnilam in the Orion belt is 410.8 Pc
Explanation:
The angle due to the change in position of a nearby object against the background stars is known as parallax. This angle is gotten when the position of the object is measured in January and then in July according to the configuration of the Earth with respect to the Sun in those months (see the image below).
The parallax angle can be used to find out the distance by means of triangulation. Making a triangle between the nearby star, the Sun and the Earth(as is shown in the image below), knowing that the distance between the Earth and the Sun (150000000 Km) is defined as 1 astronomical unit:
Where d is the distance to the star.
(1)
Equation (1) can be rewritten in terms of d:
(2)
Equation (2) represents the distance in a unit known as parsec (pc), which is the distance of a star with a parallax angle of 1 arc second.
For the case of the star Alnilam in the Orion belt ( 1340 light-years):
Since 1 parsec is equivalent to 3.262 light-years, therefore:
⇒
Notice how both , Light years and parsecs are units for distance.
Key terms:
Parsec: Parallax of arc second.
Light-year: Distance traveled by light in one year.
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Answer:
b) Best explanation is -- both balls have same momentum and hence has equal stings to be felt
Explanation:
The question is ;
A friend tosses a ball to you with a speed V. When you catch the ball , you feel a noticeable sting in your hand, due to the force required to stop the ball.
a0 If you catch the second ball with a mass 2m and speed V/2. is the sting you feel , is greater than. less than or equale to the sting you felt when you caught the first ball ? The time required to stop the two balls is same.
b) Choose the best explanation from among the following;
i) The second ball has less KE, since KE depends on V2, and hence less sting.
ii) The two balls have the same momentum , and hence produce the same sting.
iii) The second ball has more mass and hence produces the greater sting.
<em>Solution:</em>
The momentum can be found from KE = 1/2 m = 1/2
÷ m
= /2m
or KE= /2m
==> P= --- (1)
Now momentum for first ball;
mass = m1=m
Speed V1 = V
and KE = 1/2 m
Putting in eq (1)
==> P1=
==> P1 = mV
Momentum for second ball;
Mass m2= 2m
Speed V2 = V/2
KE = 1/2 m = 1/2 (2m)
=
For momentum putting value of KE and mass m =3m in eq 1;
==> P2 =
==> P2 = mV
So we see that both the balls have same momentum i-e change in momentum is zero - or we can say both ball hit the hand with same force -- hence with same sting to be felt.
b) Best explanation is -- both balls have same momentum and hence has equal stings to be felt