Answer:
1)SI is coherent system of units
2) SI is rational system of units
Answer:
Part a)

Part b)

Explanation:
Part a)
If block is sliding up then net force must be zero and friction will be in opposite to the direction of motion of the block


so we have





Part b)
If block is sliding down then net force must be zero and friction will be in opposite to the direction of motion of the block


so we have





Answer:
50
Explanation:
The mechanical advantage of a machine is given by

where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find

Answer:
Alfred Wegener
Explanation:
Alfred Wegener is a german meteorologist who proposed the theory that the continents drifted, and he presented it to the German Geological Society on January 1912.
Each side has to have at least 44 horses
F61160 N. This is further explained below.
<h3>What is the force?</h3>
Generally, We are only interested in the component that operates horizontally since the vertical components all cancel each other out. The pressure difference works on the hemisphere to generate a normal force all over the surface, but we are only concerned with that force's horizontal component. This may be determined by supposing the hemispheres to be two flat circular plates of the same radius as the hemispheres that have been forced together.
Therefore, force is equal to pressure multiplied by area, which is
F= (970 -15 )( * (0.45 m)2)
F=60754 N for each side.
Therefore, each side has to have at least 44 horses
44* 1390 = 61160 N
Read more about force
brainly.com/question/13191643
#SPJ1