The block is in equilibrium, so the net forces parallel and perpendicular to the surface are
∑ F[para] = F[normal] - mg = 0
∑ F[perp] = F[pull] - F[friction] = 0
where mg is the weight of the block. It follows that
F[normal] = mg = (5 kg) (9.8 m/s²) = 49 N
and so the frictional force has magnitude
F[friction] = 0.25 F[normal] = 12.25 N ≈ 12 N
Radiation and Convection transfer energy from the core to the photosphere. This is because energy from the core moves through a thick layer called the radiative zone. Also in the convection zone energy moves mainly by convection. Rising currents of hot gas in the convection zone carry energy toward the Sun's surface.
Answer:
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Answer: C. They are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere
Explanation:
Sunspots appear dark because they are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere.
Sunspots are typically cooler than their surroundings. For example, the temperature of a large sunspot can be about 4,000 Kelvin which is lower than the temperature of the photosphere around it which is about 5,800 Kelvin.
240 = 0+1/2 (-9.8t
240 = -4.9t
<span>240/-4.9 = t</span><span>
</span>49.0 = t
t= 7.0s