We know that the source of light in the universe is the Sun. Hence, the light we see as moonlight travels from the Sun's surface, to the moon, then to Earth. So, before being able to solve this problem, we have to know the distance between the Sun and the moon, and the distance between the moon and Earth. In literature, these values are 3.8×10⁵ km (Sun to moon) and 384,400 km (moon to Earth). Knowing that the speed of light is 300,000 km per second, then the total time would be
Time = distance/speed
Time = (3.8×10⁵ km + 384,400 km)/300,000 km/s
Time = 2.548 seconds
Thus, it only takes 2.548 for the light from the Sun to reach to the Earth as perceived to be what we call moonlight.
<span>First, she should put the sample in a test tube and place it in a centrifuge. This would cause the red blood cells to move to the bottom because of their higher density. Next, she would be able to decant the plasma and analyze it separately from the red blood cells.</span>
Weight = mass * gravity = 60 kg * 3.75 m/s² = 225 N
<span>Option D.</span>
Answer:
The acceleration at the astronaut's head decreases.
Explanation:
Since the centripetal acceleration equals acceleration due to gravity,
a = g = GM/R². since a changes infinitesimally from his foot to his head, we differentiate a with respect to r to get da/dr = -2GM/R³.
So, da, the change in acceleration = -2GMdR/R³ = -2gdR/R = -2 × 9.8/6.4 × 10⁶ m = -3.0625 × 10⁻⁶dR m/s².
Since dR = height of astronaut = 1.80 m, da = -3.0625 × 10⁻⁶ × 1.8 = -5.5125 × 10⁻⁶ m/s².
So the acceleration at the astronaut's head is g + da = 9.8 - 0.0000055125 = 9.7999944875 m/s².
So the acceleration at the astronaut's head decreases.
Answer:
Stage fright
Explanation:
Stage fear is one that a person experiences when he feels exposed to what others are going to say. This feeling is characterized by the fear of public speaking. Some common causes are large crowds or stress associated with an important presentation where people can stutter and do a poor job.