Biomechanics Final Exam- Shim
T/F: while spinning with arms out on a frictionless chair, you will start spinning faster when bringing the arms closer to the body and produce a GREATER ANGULAR MOMENTUM
False
What force causes radial acceleration
centripetal force
the major advantage of fosbury high jump technique over others is the reduction of ______ height
clearance
Pair of equal, oppositely directed forces that act on opposite sides of an axis of rotation to produce torque is called a
couple
What are two types of quantities where the sum of each must be zero to maintain a state of equilibrium
forces and torques
What two fluid forces are formed due to pressure difference
form drag and lift
Torque is also called ______ force
momentum
_____ is inverse of speed and is commonly quantified as minutes per km or minutes per mile
pace
The _____ is equal to the change in energy that it produces in the object acted on
work of a force
Lifting the head up is an example of which class of lever
1st class
When a ball thrown straight up and reaches its peak height, the kinetic energy is ____ and the vertical acceleration is _____
0J, -9.81 m/s^2
If a 2 kg soccer ball kicked in the air with 9.81 m/s vertical velocity at impact, how many seconds after the impact will the ball reach peak? (wind is blowing horizontally at 10m/s)
1 sec
Which of the following is NOT a correct definition of momentum
Ability to reduce pressure
An area bound by the outermost regions of contact between a body and support surface defines what?
Base of support
Which of the following statements is TRUE
Center of gravity can lie outside the body
A diver is doing a pike front dive with her arms fully extended overhead and her body straight at the instant of takeoff with some amount of angular momentum (H ≠ 0). During the first half of the dive, she brings her hands down toward her feet (i.e., from straight to pike position). What happens to each of the following quantities during that time? THE MOMENT OF INERTIA ABOUT THE LONGITUDINAL AXIS THROUGH HER COG
Decrease
A diver is doing a pike front dive with her arms fully extended overhead and her body straight at the instant of takeoff with some amount of angular momentum (H ≠ 0). During the first half of the dive, she brings her hands down toward her feet (i.e., from straight to pike position). What happens to each of the following quantities during that time? THE MOMENT OF INERTIA ABOUT THE TRANSVERSE AXIS THROUGH HER CENTRY OF GRAVITY
Decrease
Which of the following statements is TRUE
Friction is a passive force
What force acts perpendicular to the direction of relative flow?
Lift
Which of the following is NOT true
Linear velocity = angular velocity x radius of gyration
What can be generally done to increase stability
Lower COM
Which of the following statements is false?
Moment of inertia does not impact torque
Which of the following is not true about the value of -9.81 m/s^2 of an object in projectile motion
Object can be accelerating or decelerating
What is the advantage of the hitch-kick technique (running in the air) in long jump?
Optimal body position at landing
What shows the correct unit?
Power = watts
Which of the following is NOT a direct influencing factor of projectile motion (ignoring air resistance) at the point of release?
Release acceleration
A diver is doing a pike front dive with her arms fully extended overhead and her body straight at the instant of takeoff with some amount of angular momentum (H ≠ 0). During the first half of the dive, she brings her hands down toward her feet (i.e., from straight to pike position). What happens to each of the following quantities during that time? THE TORQUE PRODUCED BY GRAVITY ON HER BODY ABOUT THE TRANSVERSE AXIS THROUGH HER COG
Same
Which of the following statements is true?
Statics is studying the system with zero acceleration
T/F: Instantaneous velocity of basketball free throw at release is greater than the instantaneous velocity of the ball before entering the basket
TRUE
T/F: a defensive lineman in football is trying to block a forward pass. He would be able to reach higher with one hand than with two
TRUE
T/F: gravity or gravitational force is equal to -9.81m/s^2
TRUE
T/F: the direction of radial and tangential acceleration are 45 degrees to eachother
TRUE
T/F: when extending forearm slowly during arm curl, the triceps is active concentrically
TRUE
T/F: when muscles produce eccentric contraction, they produce negative work
TRUE
The angle of attack of a projectile affects not only lift but also drag
TRUE
Which of the following is NOT a correct definition
Torque is moment of inertia times angular velocity
In the standing position, from the moment you bend your knees and coming to a stop at 90 degrees, the body initially accelerates and then decelerates to stop. When is the transition point from deceleration to acceleration
When acceleration is zero
Which of the following is a scalar
Work
What shows the incorrect unit
Work = Nxs
If velocity is constant, what is NOT true?
Work is conserved
Which of the following statements is FALSE
Work is the capacity to give power
Which ball will reach a higher peak before making contact on the court
all
Which ball will likely posses the least amount of linear momentum after it contacts the court
back spin
Which of the following is the unit of angle that must be used to compute linear velocity?
degrees
T/F: If a long jumper can maintain maximum running speed, the optimal takeoff angle would be 30 degrees
false
T/F: You can hit a golfball farther with a longer club because you can swing faster
false
T/F: conversion factor is needed to compute time parameters such as projectile flight time or running stride time
false
T/F: energy, work and power are all vectors
false
T/F: if a ball bounces up 1 m when dropped from 2 m above the ground, then it will bounce to 2m when dropped from 3 m
false
T/F: if a ball lands on a complete frictionless floor, it will lose angular momentum after the impact on the floor
false
T/F: if a person jumps straight up in a layout position with arms up but lands with arms down, the time from takeoff to peak is shorter than the time from peak to landing
false
T/F: in a vertical jump landing from initial foot contact to a complete stop, people normally bend knees to reduce the amount of change in momentum during landing
false
T/F: kinetic variables include impulse, displacement, speed, and power
false
T/F: locomotion speed is equal to stride length multiplied by stride time
false
T/F: the units for kinetic energy, impulse and work are all the same
false
T/F: when a body is in the air the torque produced on the body by gravity is increased
false
What is the main advantage of the high jumpers that are tall with long legs?
greater takeoff height
Name a couple pieces of equipment commonly used in biomechanics analysis of human motion. These were used and demonstrated in class and were also shown in many sports science videos
reaction board, force plate, tracker
The center of rotation at a given joint angle during dynamic movement is called ____ center
relative
If a ball is rolling horizontally on the ground at +5 m/s^2 and then comes to a stop, what is true?
rolling friction is acting left
Which of the following is the method that uses pre-existing data on individual segment mass and COG locations
segmental method
Which factor affects both skin drag and form drag? (increases one, decreases other)
smoothness of surface
Elbow flection during a biceps curl is an example of ____ class lever
third
Which ball will hit the court first?
top spin
When performing a somersault in gymnastics, what is the best position to assume to rotate fastest
tuck
ROLLING FRICTION IS NOT INFLUENCED BY WHICH OF THE FOLLOWING
width