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analyzing forces
using free-body diagrams
1. imagine two books sitting at rest
on top of each other on a table.
the top book has a mass of 2 kg,
the book under the top book has a
mass of 3 kg, and the table has a mass
of 20 kg. clearly there is a force of
gravity (weight) on all three objects.
in addition, because some of the
objects are in contact with other
objects, there may be forces by one
object on another object.
a) draw a free-body diagram for each
object. on each diagram, draw
arrows representing the force of
gravity and any other forces on the
object by another object (including
the floor).
b) what is the acceleration of each
of the objects?
c) what is the force of gravity
on each object?
d) what is the force on each object by
the other objects?

Explanation:

mass of top book = 2kg

mass of book under = 3kg

mass of table = 20kg

a) The diagram is in the attached file to this solution

b) Since the objects are at rest, the acceleration of each of the object is zero

c) Force of gravity giving that g = 10 is

for the top book = 2*10 = 20N

for the book under = 3*10 = 30N

for the table = 25*10 = 250N

d) for the top book = 2*10 - 2*10= 0N

for the book under = 3*10 - 3*10 = 0N

for the table = 25*10 - 25*10 = 0N

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