A Man with Upper Body Mass of 40 Kg Bends

question 20

Multiple Choice

A man with upper body mass of 40 kg bends forward at the hip at an angle of 60° from the vertical, keeping his legs in a vertical position and his back straight. The effective pivot point is the pelvic cavity, located 6 cm from the line of the back muscles used to maintain this bending position. The centre of mass of the upper body is located 60 cm from the pelvic pivot. What is the force exerted by the back muscles?

• A)40 N
• B)200 N
• C)392 N
• D)1960 N

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Definitions:

Females

Individuals of a species that are typically characterized by the ability to produce eggs or bear offspring.

Lac Operon

An example of gene regulation in prokaryotes, involving a group of genes that are involved in the transport and breakdown of lactose in the cell.

Repressor

A substance, often a protein, that inhibits the expression of a gene.