During the first phase of acceleration we have:
v o = 4 m/s; t = 8 s; v = 13 m/s, a = ?
v = v o + a * t
13 m/s = 4 m / s + a * 8 s
a * 8 s = 9 m/s
a = 9 m/s : 8 s
a = 1.125 m/s²
The final speed:
v = ?; v o = 13 m/s; a = 1.125 m/s² ; t = 16 s
v = v o + a * t
v = 13 m/s + 1.125 m/s² * 16 s
v = 13 m/s + 18 m/s = 31 m/s
The period T of a pendulum is given by:

where L is the length of the pendulum while

is the gravitational acceleration.
In the pendulum of the problem, one complete vibration takes exactly 0.200 s, this means its period is

. Using this data, we can solve the previous formula to find L:
Answer:
The water molecule cannot escape, since the average velocity of the water molecules is less than one sixth of the escape velocity of venus.
Explanation:
The average speed of gas molecules is given by:

R is the gas constant, T is the temperature and M the molar mass of the gas.
We know that a water molecule has a mass that is 18 times that of a hydrogen atom:

So, we have:

The water molecule cannot escape, since the average velocity of the water molecules is less than one sixth of the escape velocity of venus:

I believe it’s called Alluvium! It’s where the river mouth is build up of gravel,sand,silt, and clay!!