In a classroom demonstration, a 79.2-kg physics professor lies on a "bed of nails." The bed consists of a large number of evenly spaced, relatively sharp nails mounted in a board so that the points extend vertically outward from the board. While the professor is lying down, approximately 1950 nails make contact with his body. 7. What is the average force exerted by each nail on the professor's body? A) 0.201 N B) 0.398 N C) 1.42 N D) 0.809 N E) 142 N 8. If the area of contact at the head of each nail is 1.26 x 10-6 m2, what is the average pressure at each contact? A) 1.58 x 105 Pa B) 1.27 x 106 Pa C) 2.40 x 104 Pa D) 4.82 x 104 Pa E) 3.16 x 105 Pa

In a classroom demonstration, a 79.2-kg physics professor lies on a "bed of nails." The bed consists of a large number of evenly spaced, relatively sharp nails mounted in a board so that the points extend vertically outward from the board. While the professor is lying down, approximately 1950 nails make contact with his body. 7. What is the average force exerted by each nail on the professor's body? A) 0.201 N B) 0.398 N C) 1.42 N D) 0.809 N E) 142 N 8. If the area of contact at the head of each nail is 1.26 x 10-6 m2, what is the average pressure at each contact? A) 1.58 x 105 Pa B) 1.27 x 106 Pa C) 2.40 x 104 Pa D) 4.82 x 104 Pa E) 3.16 x 105 Pa