Mendel made conclusions about inheritance without ever seeing chromosomes or knowing about DNA. Which technology has enabled the
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Answer:
The magnitud of the force is 124.8N.
Explanation:
First we have to find the value of the static friction coefficient, when the external force F is applied to upper block (i will call it A Block) we have a free body diagram as the one shown in the figure i attached, so since this block has no aceleration in any direction the force F should be equal to the friction force between A and B block, one we noticed this we can use the equation for the Friction force to find the coefficient:
μs
and again, since the block has no acceleration the normal between A and B block should be equal to the weigth of the first block, so we have:
replacing this we have:
μs
μs*
and μs
now it's time to see the free body diagram for the b block, if we now apply the F force to the B block the diagram should look like in the figure.
the color of the arrow gives you an idea of where the force comes from, the blue ones comes from the B block, the red ones from the A block and the brown ones from the ground.
now for the B block you can see two friction forces, one for the ground and one for the A block, both of these directed bacwards, and two normal forces, again one for the ground and one for the A block but the normal force for the A block is aiming downwards.
again we use the fact that the block is not accelerating in any direction so the sum of the forces in x and y direction have to be 0, so:
This is the new external F force that we are looking for:
we know Friction2(AB) because we found that in the previous block so:
*μs
for the other friction we have to use the equation:
*μs
from y axis we have:
we found the value of Normal(AB) with the previous block so:
and:
*μs
*μs
*μs+μs*
*μs
and since: μs*
the new F force would be:
*μs
Friction:
Friction is the resistive force that acts on the body in a direction opposite to the direction of motion of the same object.
Laws of friction:
1. The frictional force acting on the object is proportional to the normal force acting on the object.
For example, if the object of mass m is moving along the horizontal surface, the normal force acting on the object is mg.
Thus, the frictional force acting on the object is,
where F_N is the normal force acting on the object,
The diagrammatic representation of the frictional force acting on the object is,
2. The frictional force acting on the object depends upon the nature of the surface in contact with the object.
3. The frictional force does not depend upon the area of contact of an object with the surface.
4. The kinetic friction acting on the object is independent of the velocity of the object.
5. The coefficient of static friction is more than the coefficient of kinetic friction.
Two factors on which the frictional force depends are:
1. The frictional force depends on the adhesion between the two bodies in contact.
2. The frictional force acting on the depends upon the roughness of the surface on which the object is moving.
