Complete Question
The complete question is shown on the first uploaded image
Answer:
a
The torque produced by the pile of rocks is
b
The distance of the single for equilibrium to occur is
Explanation:
From the question we are told that
The mass of the left rock is 
The mass of the rock on the right 
The distance from fulcrum to the center of the pile of rocks is 
Generally the torque produced by the pile of rock is mathematically represented as

Substituting values
Generally we can mathematically evaluated the distance of the the single rock that would put the system in equilibrium as follows
The torque due to the single rock is

At equilibrium the both torque are equal

Making
the subject of the formula

Substituting values
In an uniform circular motion, the direction of the net force on the object is radially inward, passing through the center of the circle.
Not having clean water to drink or bath. Also some organizations that live in the water might die because the water is polluted and that would be toxic form them
The final mass after decay can be obtained by using under given relation:
half life period of As-81 = 33 seconds
mf = mi x (1/2^n)
= 100 x ( 1/2^(43.2/33))
= 40.4 %
E. all of the above
An umbrella tends to move upward on a windy day because _<span>A. buoyancy increases with increasing wind speed </span>
<span>B. air gets trapped under the umbrella and pushes it up </span>
<span>C. the wind pushes it up </span>
<span>D. a low-pressure area is created on top of the umbrella </span>