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Multiple choice physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

In which of the following lists are the units an order from LONGEST to SHORTEST?

  1. light-year, kilometer, astronomical unit

  2. astronomical unit, kilometer, light-year

  3. kilometer, light-year, astronomical unit

  4. light-year, astronomical unit, kilometer
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$1$ Light year $=9.461\times 10^{15}\,m$


$1$ Astronomical unit $=1.496\times 10^{11}\,m$

$1$ kilometer $=1000\,m$

Socorrect answer is option (D).

Multiple choice physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

 _______________displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

  1. Echo

  2. Parallax

  3. Triangulation

  4. None of These
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parallax displacement or difference in the apparent position of an object vied along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

Multiple choice physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

A uniform metre scale is balanced at $40\ cm$ mark, when weighs of $25\ gf$ and $10\ gf$ are suspended at $5\ cm$ mark and $75\ cm$ mark respectively. Calculate weight of metre scale.(in gf)

  1. 50.5

  2. 72.5

  3. 52.5

  4. 80
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let W be the weight of the scale acting at the 50 cm mark. Taking moments about the pivot (40 cm): Clockwise moments = 10 gf * (75 - 40) cm = 350 gf cm. Counter-clockwise moments = 25 gf * (40 - 5) cm + W * (50 - 40) cm = 875 + 10W. Equilibrium: 875 + 10W = 350. This implies W is negative, suggesting the scale is balanced differently or the pivot is on the other side. Re-evaluating: 25 gf at 5 cm (35 cm from pivot) and 10 gf at 75 cm (35 cm from pivot). 25*35 = 875, 10*35 = 350. The weight W must be at 50 cm (10 cm from pivot). 25*35 = 10*35 + W*10. 875 = 350 + 10W. 525 = 10W. W = 52.5 gf.