Bens mass is 100 kg. He lands from a jump. His initial vertical velocity when his
feet first touch the ground is 4 m/s downward. What is the average normal contact
force that acts on Bens feet during this landing if he comes to a stop in 0.20
Most of the multiple choice questions were taken from the reading and homework. So please go
through the chapters to solve any questions you have about those. If I made a mistake and the
book does not have the answer let me know and Ill tr
Planes, Axes, Joint
REMEMBER! Locations and relative
positions of anatomical structures are
always described according to the
anatomical position even if the person is
not in anatomical position
What is biomechanics?
Why study biomechanics?
What are the branches (and sub branches) of
What are the differences between kinetic and
kinematic biomechanical analyses?
How is biomechanics related to ot
The bodys muscles produce a force in response to an external
torque. Muscles are attached to bone via tendinous insertions.
Activation of the muscle produces force, which causes the tendon
to pull on the bone. This
KNH 381 Biomechanics
Lecture 9 Levers
Levers of the Musculoskeletal System
First, second, and third class levers
Work Energy Relationship
Mechanical Energy and Work
Mechanical energy and work have the same units (joules) but
have different meanings.
Mechanical energy is a measure of the state of a system at an
instant in time as to its ability to do work.
Mechanics of biological
This is the area of biomechanics that deals with the internal
effects of forces. Often the concern is if the structures of the body
(bones, cartilage, ligaments, etc) can handle the loads placed on
it because if it cannot
KNH 381 Biomechanics
Answer the following questions by placing your answers in the spaces provided. Do all your
calculations on SEPARATE SHEETS of paper, clearly indicating which calculations go with
which problem.CLEAR hand-writing
1. KE= mv= * 2 * 20= 400 J
2. Workdone= KE+ PE= 1/2mv + mgh= * 50* 1+ 50*9.81*3.5= 1741.75 J
3. a.yes, positive(moving the same direction as the displacement)
b .concentric contraction.
c. yes, negative (moving the different direction as the dis
Question 21 A weightlifter is attempting to lift a 200 N barbell. The moment arm of the barbell
about the elbow joint is 40 cm. The moment arm of the elbow flexor muscles is 4 cm. How much
force must be produced by these muscles to hold the 200 N barbell
1.m=10kg-> W=mg=9.81*10=98.1N (gravity is pulling the weight down with a force of 98.1N)
You are pulling up with a force of 108.1 N. Combine the upward and downward forces to get a
resultant force of 10 and put that into F=ma
F=ma= -> 10 = 10a=1