Ch 2. Basic Biomechanics

Question 1

Carrying a heavy object across one’s shoulders creates what force through the lower extremities?

Answer 1

compression

Question 2

Which of the following combinations of forces are imposed when carrying a heavy object in the right hand?
a. arm and trunk compression
b. arm and trunk rotation
c. Right arm traction and right-sided trunk compression
d. right arm compression and right-sided trunk traction

Answer 2

C. Right arm traction and right-sided trunk compression

Question 3

To push a large heavy box across the floor, an individual should strand:
a. parallel to the desired line of motion
b. Perpendicular to the desired line of motion

Answer 3

a. parallel to the desired line of motion

Question 4

Seat belts in cars are designed to prevent injuries related to which of Newton’s law?
a. Law of inertia
b. Law of acceleration
c. Law of action and reaction

Answer 4

a. Law of inertia

Question 5

Why does carrying a load on one’s shoulders affect stability?
a. Increased traction through joints
b. COM is higher
c. Newton’s second law
d. Shorter resistance arm

Answer 5

b. COM is higher

Question 6

Standing on the right lower extremity, flex the left knee so the heel moves closer to the buttocks. this creates which class of lever at the left knee?
a. First
b. second
c. third

Answer 6

c. third

Question 7

Standing on the right lower extremity, extend the left knee from the position with the heel near the buttocks. This creates which class of lever at the left knee?
a. first
b. second
c.third

Answer 7

b. 2nd

Question 8

An individual is using a hand truck to move heavy boxes down a flight of stairs. the individual stands on the step above the hand truck, rolling it over the edge of the step and lowering it to the next lower step. Which class of lever is being used?
a. first
b. second
c. third

Answer 8

a. 1st

Question 9

Rather than using a hand truck, the individual decides to lower a heavy box from a second-floor window using a pulley attached to the overhang of the roof. The individual attaches the rope to the box to the ground. the pulley arrangement is using which class of of lever to lower the box to the ground?
a. first
b. second
c. third

Answer 9

a. first

Question 10

using figure 2-42 answer the following questions
a. in figure 2-42a identify the force, resistance, and axis.
b.identify the approximate center of gravity
c. identify the FA and RA in both figures
d. in which figure is the resistance arm the longest?
e. is the luggage in (A) or (B) easier to pull? why?

Answer 10

a. Force is the person, resistance is the luggage and cart, and the axis is the wheel.
b. The COG in Figure 2-42A is approximately at the top of the suitcase
c.In both figures the length of the force arm is the perpendicular distance from the axle of the wheel to the COG of the luggage
d.Figure 2-42A
e.in figure 2-42B, theRA is shorter, so its easier to pull the lugage