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