Answer
(a) The net upward force is 50N.
(b) The net upward force is 650N.
(c)
Work Step by Step
(a) Formula to find the forces acting on the person is that the net upward force must be equal to the net downward force.
The net downward force is the weight of the person = 600N
The upward forces are the force exerted by the seat(500N), the forces (upward) on her arms(25N+25N=50N), and the force on her feet (Fe).
The net upward force is calculated as 500N+50N+Fe=550N+Fe
We must have 600N, so the upward force must be 50N.
(b) Formula to find the forces acting on the chair is that the net upward force must be equal to the net downward force.
The net downward force is the weight of the person = 600N, the weight of the chair is given as 100N.
The net force will be 600N+100N=700N
The upward forces can be determined from the upward force exerted by the armrest of the chair and the force exerted by the floor on her chair (Fc).
The net upward force is calculated as 50N+Fc
We must have 700N, so the upward force must be 650N.
(c)
Where, s stands for women and the chair, f is the floor, and e is the earth.
