Given that :
Power (P) = 30 W ,
time (t) = 40 s,
Work = ?
we know that, power is defined as rate of doing work
Power = Work ÷ time
=> Work = Power × time
= 30 × 40
<em> W = 1200 J</em>
The characteristics of stars that can be determined by analyzing a star's spectrum - Doppler shift, temperature, size, composition, and rotation.
1- Rotation: The star's rotation creates a broadening of the spectral lines, which can be used to determine the star's rotation.
2- Temperature: Measure the relative strengths of spectral lines to determine a star's spectral class which corresponds to temperature.
3- Doppler shift: The Doppler shift of the star is determined by its radial velocity.
4- Size: Measure the width of spectral lines. If the lines are narrow, the star's diameter is large. If the lines are wider, the star's diameter is smaller.
5- Composition: Computer models and temperature are used to determine elemental abundances from relative strengths of absorption lines in a star's spectrum.
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Measure the distance between an object and the lens after using the lens to focus on it. The focal length is at this range.
<h3>How simple is it to determine a lens's focal length?</h3>
Focus a far-off object on a wall by adjusting the convex lens up and down along the scale. The picture that forms on the wall is very close to the lens' focus, and the metre scale can be used to read how far away the lens is from the image. This approximates the lens's focal length.
<h3>How do you calculate a concave lens's focal length?</h3>
The formula f=uv/u-v is used to get the focal length of the concave lens using the values of u and v.
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Centripetal force needed to move mass 'm' in a circle with radius 'r' at speed 'v' is
F = m · v² / r
F = (85 kg) ·(15 m/s)² / (20 m)
F = (85kg · 225m²) / (20 m·s²)
F = (85 · 225 / 20) (kg·m² / m·s²)
F = 956.25 kg·m/s²
F = 956.25 Newtons
Just learned this in chemistry. There are no subscripts, therefor each element only has 1 atom. Na has 1, O has 1 and H has one. There are 3 atoms.
Answer-3