Thai Sikh International School
E-Learning Programme – Online
Assignment – 04/04/2014
Name
: Subject :Physics
1. (a)
Complete the
following statement:
The
moment of a force about a point is
....................................................................................
multiplied by
..........................................................................................................................
(b) Fig. 3.1
shows a uniform iron bar B of weight 30 N and length 1.40 m. The bar is being
used to
lift one
edge of a concrete slab S. A stone, placed 0.20 m from one end of B, acts as a
pivot.
A force of 40 N pushing down at the other
end of B is just enough to lift the slab and hold is
shown.
(i) On Fig. draw an arrow to show the weight of bar B acting
from its centre of mass.
(ii) State the distance d of the
centre of mass of bar B from the pivot.
d =
...........................................................
(iii) Calculate the total clockwise moment,
about the pivot, of the forces acting on bar B.
total clockwise moment =
..........................................................
(iv) Calculate the downward force which the
slab S exerts on the end of bar B.
force = ...........................................................
(v) Suggest a change to the arrangement in Fig. that would
reduce the force required to
lift the slab.
...........................................................................................................................................
.......................................................................................................................................
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