Biomedical Engineering Reference
In-Depth Information
Fig. 1.11
Two forces are
applied on the block: the
force of gravity (weight)
W
and the normal force
N
whose sum gives zero
resultant, as the block is at
rest. The normal force
N
*is
the reaction force to the
action force
N
. The reaction
to
W
is applied on the center
of the earth and is not
represented here
W
N
N*
Example 1.3
Consider two blocks: block A, which weighs 5 N, is on the table.
Block B, weighing 10 N, is on top of block A as shown in the figure of Example 1.3.
Analyze the forces that act on each block separately. Finally, determine the total
contact force exerted by the two blocks on the table.
B
10 N
A
5 N
N
B
= 10 N
N
A
= 15 N
B
A
W
A
= 5 N
W
B
= 10 N
N
B
* = 10 N
N
A
* = 15 N
As the two blocks are at rest, the resultant of applied forces on each block must
be zero. The weight of the table was not considered, but only the contact force that
