Answer:
a) As the chicken is still, the displacement is zero, which implies that the work is zero.
b) as the person is still there is no displacement therefore the work is zero
c) Lagraua applies a vertical force and the displacement is vertical, therefore the Work is positive
d) the force of gravity is directed downwards and the displacement is upwards, therefore the angle between it is 180º and the 180º fly is -1. Consequently the lock is negative
e) when the person meticulously feels the upward force and the displacement is downward, therefore the work is negative
Explanation:
Work is defined by the expression
W = F. r
bold letters indicate vectors, we can write this expression as a module
W= F r cos θ
where is at the angle between force and displacement.
Let's apply this expression to the different cases
a) As the chicken is still, the displacement is zero, which implies that the work is zero.
b) as the person is still there is no displacement therefore the work is zero
c) Lagraua applies a vertical force and the displacement is vertical, therefore the Work is positive
d) the force of gravity is directed downwards and the displacement is upwards, therefore the angle between it is 180º and the 180º fly is -1. Consequently the lock is negative
e) when the person meticulously feels the upward force and the displacement is downward, therefore the work is negative
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