(b)
Fig 8.1 shows a spanner being used to unscrew a nut from a bolt.
(c)
(í)
6 cm
A
10 cm
B
Fig 8.1
Explain why it is better to push the spanner at B rather than at A.
(The arrows marked A and B show the direction of the applied
forces.)
[1]
(ii) A force of 120 N is applied at B. Calculate the moment of this force
about the centre of the bolt.
132
(ii)
Moment of force =
.Nm [2]
The nut and bolt are so rusty that the nut cannot be turned. What
effect may
be produced on the nut and bolt by the application of the
force?
.[1]
Fig 8.2 shows two masses which are suspended at the ends of a metal beam
which is 2m long.
P
790g
2m
pivot
Q
1225 g
Fig. 8.2
The beam is pivoted 1.2m from end P. Assuming that the beam is perfectly
balanced on the pivot, calculate the mass of the metal beam.
​