Answer :
Final answer:
The question is asking for calculation of the normal forces exerted on a crate by the floor and on a person by the crate. The normal force exerted by the floor equals the combined weight of the crate and person, while the normal force exerted on the person equals their own weight.
Explanation:
The student is asking for the magnitude of the normal force exerted in two different situations involving a crate and a person. The normal force is the force exerted by a surface to support the weight of an object resting on it. It acts perpendicular to the surface.
(a) Normal force by the floor on the crate
The total weight on the crate is the sum of the weight of the crate and the weight of the person. This can be calculated as the sum of the mass of the crate and the mass of the person times the acceleration due to gravity (9.8 m/s2). The normal force by the floor on the crate would be equal to this total weight if there is no acceleration in the vertical direction.
(b) Normal force by the crate on the person
The normal force by the crate on the person is just the weight of the person since the crate is just a medium and does not change the force exerted on the person by gravity. The person's weight can be calculated by multiplying the mass of the person by the acceleration due to gravity, which provides the magnitude of the normal force the crate exerts on the person.
Answer:
FN = 997.64 N :Force that the floor exerts on the crate
Fcp = 636.02N, vertical and upaward
Explanation:
Wp: person Weigth (N)
Wc: crate Weigth ( N)
FN: Normal force
Calculated of the weight
Wc=(36.9kg)(9.8 m/s²) = 361.62 N
Wp= (64.9kg)(9.8 m/s²) = 636.02N
(a) Force that the floor exerts on the crate
For free body diagram of the crate+person
∑Fy=0
FN-Wc-Wp = 0
FN-361.62 N-636.02N= 0
FN = 997.64 N :Force that the floor exerts on the crate
(b) For free body diagram of the crate
Fpc: Force of the person on the box
∑Fy=0
FN-Wc-Fpc = 0
997.64 N-361.62 N = Fpc
Fpc =636.02N :Force of the person on the crate(vertical and downaward)
Newton's third law or principle of action and reaction :
Force of the person on the crate = - Force of the crate on the person
Fpc = - Fcp
Fcp:Force of the crate on the person
Fcp = 636.02N, vertical and upaward