Answer:
the first one is Primary
the second one I think it's Mature but I don't know
Answer:
the answer is calcium....
Answer: please see attached work.
Explanation: please see attached work. Assuming 500 sheets of paper = 20 lb. (typicical value).
Answer:
The force is 
Explanation:
From the question we are told that
The mass of the block is 
The coefficient of static friction is 
The coefficient of kinetic friction is 
The normal force acting on the block is

substituting values


Given that the force we are to find is the force required to get the block to start moving then the force acting against this force is the static frictional force which is mathematically evaluated as

substituting values


Now for this block to move the force require is equal to
i.e

=> 
Explanation:
'What is the magnitude of the force needed to stop the horses and bring the box into equilibrium?' ≈42N; according to the vectors rules.
'Where would you locate the rope to apply the force?' - in point D.
PS. zoom out the attached picture.