BIOMECH 2 USE

_______ is a rotary force produced by an eccentric force and is the cause of angular motion.

Torque

_________ is a simple form of motion in which the object rotates about an axis.

Angular motion

Which of the following statements about moment arm is incorrect?

A) Moment arm is the shortest ( perpendicular) distance from the axis of rotation to the line of action of the force.

B) Moment arm of a muscle changes as the joint angle changes.

C)Moment arm of a muscle becomes minimum when its angle of pull is 90 degrees.

D)For the muscles causing the same type of joint motion, the optimal joint angle providing the maximum moment arm varies from one muscle to another.

C)Moment arm of a muscle becomes minimum when its angle of pull is 90 degrees.

Over 95% of the joints found in the human body form _____ class levers, which are characterized by disadvantage in force but advantage in motion (displacement or velocity).

3rd

Which of the following joint- DOF combinations is incorrect?

A) Saddle-2

B) Ball and Socket-3

C) Gliding-1

D) Condyloid-2

E) Hinge-1

C) Gliding-1

In human machine system _____ act as motors

Skeletal muscle

Which of the following is not a role assumed by skeletal muscles?

A) Agonist

B) Equalizer

C) Stabilizer

D) Antagonist

B) Equalizer

Which of the following is not a component of Hill's muscle model?

A) Parallel elastic component

B) Serious elastic component

C) Series viscous component

D) Contractile component

C) Series viscous component

The order of motor unit recruitment during an activity is ________.

SO > FOG > FG

Which of the following is not a basic property of the musculotendinous (muscle-tendon)

A) Extensibility

B) Elasticity

C) Repeatability

D) Contractility

C) Repeatability

Which of the following statements about muscular power is incorrect?

A) Muscular power is affected by both muscle force and the movement speed.

B) Individuals with predominance of slow-twitch (ST) fibers (motor units) generate more power at a given load than individuals with high percentage of fast-twitch (FT) composition since ST fibers are characterized by slower but higher maximal tension.

C) Sprinting requires muscular power rather than muscular strength, particularly in the hamstrings and gastrocnemius.

D)The strongest shot-putter on the team is not necessarily the best shot-putter.

B) Individuals with predominance of slow-twitch (ST) fibers (motor units) generate more power at a given load than individuals with high percentage of fast-twitch (FT) composition since ST fibers are characterized by slower but higher maximal tension.

The area of study in biomechanics that deals with the description of motion is ____________

Kinematics

A vector quantity has both __________ and ____________

Magnitude and direction

Which of the following is not a kinematic quantity?

A) Velocity

B) Displacement

C) Force

D) Angular acceleration

C) Force

According to the figure below, sin θ =

A) adj/hyp

B) opp/hyp

C)opp/adj

D)adj/opp

B) opp/hyp

The procedure to break a vector down to perpendicular components is _________.

Vector decomposition

An orienteer shows two consecutive displacements of 100 m and 150 m. What is the magnitude of the overall (resultant) displacement?

A) 250 m

B) 180.28 m

C) -50 m

D) need more information.

A) 250 m

Velocity= ( ________/ __________ ) ; where as speed ( _______/ _______ )

( linear displacement/ elapsed time)

(linear distance/ elapsed time)

Which of the following statements about displacement and distance is incorrect?

A) Displacement is defined as the change in position

B) The standard unit of both displacement and distance is meter (m)

C) Displacement is a vector quantity, while distance is a scalar quantity

D) Displacement is the length of the actual path taken

E) None of the above

D) Displacement is the length of the actual path taken

The tangential acceleration a point on a rotating object experiences is due to the change in the ______ of the tangential velocity.

magnitude

A runner completes a full lap around a 400-m track. What is her linear displacement?

A) 400m

B) 400 x 2 rad

C) 0 m

D) need more information

C) 0 m

Which of the following statements about velocity is incorrect?

A. velocity describes how fast and in which direction an object is moving.→speed

B. Change in velocity means acceleration.

C. A zero velocity means "no net motion".

D. A negative vertical velocity means the object is moving downward.

E. None of the above

E. None of the above

Running velocity can be expressed as (stride frequency (rate) x [stride length]. Therefore, one can increase the running velocity by increasing either if these. In the relatively low velocity range, as the running velocity increases _____________ increases perdominantly.

stride length

Which of the following statements about acceleration is incorrect?

A) Acceleration is defined as the rate of change in velocity

B) Acceleration can be caused by the change in either the magnitude or direction of the velocity

C) Acceleration can have both magnitude and direction

D) When acceleration is 0, velocity is also 0

D) When acceleration is 0, velocity is also 0

Carl Lewis changes his velocity from 8 m/s to 11 m/s. Michael Johnson changes his from 7 m/s to 10 m/s. Whose acceleration is higher?

A) Carls

B)Michaels

C) Their accelerations are equal

D) Need more information

D) Need more information

If cos θ = 0.354 (0 degrees < θ < 90 degrees)

θ= __________

69.27

180 degrees is equal to ______ rad

π

A negative vector acceleration can mean

_________________

________________

Slowing down in the positive direction and Speeding up in the negative direction

Which of the following statements about angular motion is incorrect?

A) If the initial angular position of the golf club at address is 3m/2 and that at the end of backswing is /4 rad, the angular displacement during the backswing is -5/4 rad.

B) Angular motion always involves an axis of rotation.

C) It is the convention to measure the angular position from the horizontal

D) A counterclockwise rotation gives a negative angular displacement.

D) A counterclockwise rotation gives a negative angular displacement.

Which of the following statements about radian (rad) is true?

A) It is approximately 57.3°.

B) It is the size of the angle subtended by an arc of radius length.

C) It is the standard unit of angular position & displacement.

D) All of the above.

D) All of the above.

Which of the following is different from the others?

A) 270°

B) 3/4 revolution

C) 3/2 rad

D) 3 parsec.

D) 3 parsec.

If the angular velocity of the bat increases. what will happen to the linear velocity of the end of

A) Increases.

B) Decreases.

C) Stays the same.

D) End of the bat has no linear velocity.

A) Increases.

When the instantaneous angular acceleration is 0,

__________ remains constant.

A) angular inertia

B) angular position

C) angular velocity

D) angular distance

C) angular velocity

If angular acceleration is constant (non-zero), then angular velocity must be

A) constant

B) increasing or decreasing

C) equal to zero

D) none of the above

B) increasing or decreasing

TWU's Venus Pioneer is trying to hit a softball with her bat. The linear velocity of a point at 120 cm from the axis of rotation is ________ times as large as that of a point at 100cm from it.

A) 5/6

B) 6/5

C) 1

D) Unknown.

B) 6/5

A model airplane is being flown at the end of a cord 6 m long. If the speed of the airplane remains constant, but the cord is shortened to 5.5 m. what will be the effect on the angular velocity of the cord?

A) lt will increase.

B) It will decrease.

C) It will remain the same.

D) One must know the mass of the airplane in order to answer the question.

A) lt will increase.