The diagram below shows the plan view of a door hinged at A. If a man applies a force, F, of 40 N at the end marked B, calculate the
moment of this force about A. What is the minimum force X that must
be applied at C in order to stop the door from turning? Name the
principle applied to solve this problem.
'1.8 m
B
A
1.2 m

f=ma newton

f=100x2.5=250n

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