Answer: the external agent must do work equal to -1.3 × 10⁻⁸ J
Explanation:
Given that;
Mass M1 = 7.0 kg
r = 3.0/2 m = 1.5 m
Mass M2 = 21 kg
we know that G = 6.67 × 10⁻¹¹ N.m²/kg²
work done by an external agent W = -2GM2M1 / r
so we substitute
W = (-2 × 6.67 × 10⁻¹¹ × 21 × 7) / 1.5
W = -1.96098 × 10⁻⁸ / 1.5
W = -1.3 × 10⁻⁸ J
Therefore the external agent must do work equal to -1.3 × 10⁻⁸ J
Answer:
Oprion A
The length of time over which the conditions are measured
Explanation:
Weather captures the daily atmospheric conditions over a short duration hence it is short-term. Climate is the average of weather and covers a longer duration hence long-term. Therefore, what differentiatea these two is the length of time over which the conditions are measured.
Answer:
a)
b)
c)
d)
Explanation:
From the question we are told that:
Population percentage 
Sample size 
Let x =customers ask for water
Let y =customers dose not ask for water with their meal
Generally the equation for y is mathematically given by

Generally the equation for pmf p(x) is mathematically given by

a)
Generally the probability that exactly 6 ask for water is mathematically given by


b)
Generally the probability that less than 9 ask for water with meal is mathematically given by




c)
Generally the probability that at least 3 ask for water with meal is mathematically given by

![p(x\geq3)=1-[p(0)+p(1)+p(2)]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5Bp%280%29%2Bp%281%29%2Bp%282%29%5D)
![p(x\geq3)=1-[0.00001+0.0015+0.0106]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.00001%2B0.0015%2B0.0106%5D)
![p(x\geq3)=1-[0.0122]](https://tex.z-dn.net/?f=p%28x%5Cgeq3%29%3D1-%5B0.0122%5D)

d)
Generally the mean and standard deviation of sample size is mathematically given by
Mean

Standard deviation


Answer:
Backwash effect
Explanation:
Your friend moved along the shore due to ; The swash effect and the Backwash effect
Swash effect is caused by the upsurge of water up along the slopping front of the beach and this same upsurge in water moves back into the beach in what is known as the backwash effect hence the movement of your friend form where they were in the surf zone to another position still within the surface zone is caused by the BACKWASH EFFECT