Answer:
Explanation:
a) The second arm measures the minutes. The difference between 9:17:30 and 9:15:00 is 2 minutes 30 seconds. This means the second arm would have revolved 2.5 times.
The circumference = 2πr= 2π(13.5 cm) = 84.823 cm
Distance = 2.5 × 84.823 cm = 212 cm = 2.12 m
b) Displacement of an object is the shortest distance between the initial and final point. Since the second arm revolves 2 and half times, we use only the half times (a semicircle)
Displacement for semicircle = 2r = 2(13.5) = 27 cm
c) Average speed = distance / time
time = 2 minutes 30 seconds = 150 seconds
Average speed = 212 cm / 150 s = 1.41 cm/s
d) Average velocity = displacement / time = 27 cm / 150 s = 0.18 cm/s
e) number of revolutions = 100 m / circumference = 100 m / 0.848 m = 117.92
but 1 revolution = 1 minute
117.92 revolution = 117 minutes 55 seconds = 1 hour 57 minutes 55 seconds
Hence the time would be: 11:12:55
Answer: Reflection by clouds
Explanation:
Only some shortwave radiation from the sun reaches the Earth's surface because solar radiation is being reflected by thick clouds and thin clouds transmit the solar radiation.
About 31 % of solar radiation is reflected by clouds. The tiny water particle scatters 20-90 % of incoming sunlight giving them a bright white appearance.
Animals have a food chain. (sorry for my bad English)
C
Atomic radius is the distance between the center of the nucleus to the outermost orbital shell of the atom. Assume the atom is like a football stadium and the nucleus of the atom is a ball placed at the center of the pitch. The atomic radius is from the center of the ball to the edge of the football stadium.
Explanation:
This atomic radius decreases from left to right of a periodic table because of increases in protons in the nucleus along the periodic table. This increased proton count has a higher attractive force on the electron orbitals of the atom. This decreases the atomic radius
The atomic radius of atoms down a column of the periodic table increase because an extra orbital shell is added to the atoms with every period down the column.
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Answer:
51520J
Explanation:
The energy added to the piece of glass is also called heat needed to increase its temperature from 10°C to 50°C and it depends on the mass, specific heat capacity and the change in temperature.
Q=m.c.ΔT
Q=(2kg).(644J/(kg°C)).((50°C)-(10°C))
Q=51520J
