Biomechanics exam 1 - rutland
Which of the following would be harder to change direction? a) 5 kg moving at -5 m/sec b) 10 kg mass moving at 2 m/sec c) 2 kg mass moving at 12m/s
5 kg mass moving at -5 m/sec
Which of the following will lead to the greatest increase in angular momentum?
Increase torque; Increase the time the torque is applied
What is a resistance to change in velocity?
Inertia
Which of the following is an example of relative velocity?
The velocity of your car relative to another car
which of the following is a measure of inertia for a linear motion when a body is no moving?
mass
Which of the following is a measure of inertia for angular motion when a body is not rotating?
moment of inertia
Which of the following is a measure of inertia for linear motion when a body is moving?
momentum
If body A has a greater velocity than body B, then what is the velocity of body A relative to body B?
negative
What do two perpendicular axes represent?
plane
which of the following is an example of accommodating resistance
pneumatic devices
What is a body's location in a frame of reference?
position
A body's initial velocity was -20 m/sec and its final velocity was -10 m/seC) What was the average acceleration during this time?
positive
Which type of force will increase the velocity of a system
propulsive
What is a ratio between a change in one quantity and a change in time?
rate
What is represented by the slope of the force-time curve?
rate of force development
What quantity is derived from dividing one number by another number?
ratio
What is the correction factor for the opposite side of a right triangle?
sin theta
What quantity describes how fast something is moving without consideration for direction?
speed
Which of the following determines the acceleration of the center of mass?
the effective force
What variable describes how fast something is moving in a particular direction?
velocity
Which of the following quantities is a vector?
velocity
What is the correct symbol for angular velocity?
w
What is the force due to gravity?
weight
What is a push or pull by one body on another?
force
A dancer is preparing to jump. Assuming the same velocity, which take-off angle will give her the longest flight time?
greater than 45
If the landing elevation is higher than the take-off elevation, which take-off angle will give the farthest range?
greater than 45
What is represented by the area under the force-time curve?
impulse
What mechanical quantity is the product of force and change in time?
impulse
Which of the following will lead to greatest increase in angular momentum
increase angular velocity, increase MOI
which of the following will lead to the greatest increase in velocity a) Decrease the change in time; decrease the acceleration b) Decrease the change in time; increase the acceleration c) Increase the change in time; decrease the acceleration d) Increase the change in time; increase the acceleration
increase change in time, increase acceleration
Which of the following will lead to the greatest acceleration?
increase f, decrease m
Which of the following lead to the greatest increase in the moment of inertia?
increase mass, increase distance from axis of rotation
Which of the following will lead to the greatest increase in angular displacement? a) Increase the change in time; increase the angular acceleration b)Increase the change in time; decrease the angular velocity c) Decrease the change in time; increase the angular velocity
increase the change in time; increase the angular acceleration
What happens to the displacement if the velocity is increased for the same amount of time?
increases
What happens to the time to complete a movement if angular velocity is increased?
it decreases
What happens to the velocity if the acceleration is in the same direction as the direction of travel?
it increases
If a body is rotating with an w of -20 rads/sec and then changes to an w of -40 rads/sec, what can be said about the angular acceleration during this time?
it was positive
A body's initial position was +10 m from the origin and its final position was -10 m 1 second later. What was the body's displacement?
-20 min
what is the distance from the axis of rotation to the point of force application?
lever arm
Which of the following will lead to the greatest increase in linear momentum?
Decrease force; Decrease the time the force is applied
Which of the following will decrease the utilized coefficient of friction?
Decrease xFGRF ; Increase yFGRF
Which of the following will lead to the greatest increase in linear momentum?
Doubling the mass and doubling the linear velocity would have the same effect
what is the symbol for angular momentum
H
What is the correct symbol for moment of inertia?
I
Which of the following had the greatest displacement? a) Initial Position = -20 m; Mid Position = 0 m; Final Position = -20 m d) Initial Position = 0 m; Mid Position = +10 m; Final Position = +20 m c) Initial Position = +20 m; Mid Position = 0 m; Final Position = -20 m
Initial Position = +20 m; Mid Position = 0 m; Final Position = -20 m
You pause at the bottom of a bodyweight squat. What is the magnitude of the vertical FGRF during the pause?
bodyweight
Which of the following will lead to the greatest increase in angular velocity? a) Increase the change in time; increase the angular acceleration b) Increase the change in time; decrease the angular acceleration c) Decrease the change in time; increase the angular acceleration d) Decrease the change in time; decrease the angular acceleration
a
Which of the following has the greatest velocity in the x- direction?
a) magnitude of 10 with 0 degree angle
Angela has to sprint 30m to get to the ball. Which kinematic variable is most important to her success?
acceleration
What is represented by the slope of a velocity-time curve?
acceleration
What is represented by the slope of an angular velocity-time curve?
angular acceleration
What variable describes how quickly something is speeding up or slowing down its rotation?
angular acceleration
What is represented by the area under an angular velocity-time curve?
angular displacement
change in angular position
angular displacement
What is represented by the area under the torque-time curve?
angular impulse
Which of the following is a measure of inertia for angular motion when a body is rotating?
angular momentum
What is represented by the slope of an angular position-time curve?
angular velocity
Which of the following will lead to the greatest increase in the acceleration in the x- direction? a) Decrease magnitude of a; Decrease angle of a from the x- axis b) Decrease magnitude of a; Increase angle of a from the x- axis c) Increase magnitude of a; Decrease angle of a from the x- axis d) Increase magnitude of a; Increases angle of a from the x- axis
c
What is represented by the area under an angular velocity-time curve?
change in angular position
Which of the following will lead to the greatest increase in displacement? a) Decrease the change in time; decrease the velocity b) Decrease the change in time; increase the velocity c) Increase the change in time; decrease the velocity d) Increase the change in time; increase the velocity
d
What happens to the angular velocity if the angular acceleration is in the opposite direction of the direction of travel?
decreases
symbol for displacement
delta p
What is represented by the area under a velocity-time curve?
displacement
What is the physical length that a body has traveled during a period of time?
distance
A negative angular velocity means that the rotation is slowing down.
false
A negative velocity means that the body is slowing down.
false
A soccer player kicks a ball into the air. While the ball is in the air, the velocity in the x- direction is dependent on the velocity in the y- direction.
false
True or False? A braking force is always negative and leads to a decrease in velocity.
false
True or False? A larger wheel will be easier to rotate because it has a larger moment of inertia.
false
True or False? A steeper slope on an angular acceleration-time curve represents a higher velocity.
false
True or False? Acceleration is the most important variable in determining the outcome of a marathon.
false
True or False? In the vertical direction, the ground reaction force is the effective force.
false
True or False? The acceleration is negative if you are slowing down in the negative direction.
false
True or False? The acceleration is positive if you are speeding up in the negative direction.
false
True or False? The angular acceleration is positive if you are speeding up in the negative direction.
false
True or False? The effective force will always be in the body is moving.
false
True or False? The mass of a body has a bigger effect on the moment of inertia than the location of the center of mass of that body.
false
True or False? Velocity is a scalar.
false
Vectors can be added together using the rules of algebra.
false
Which of the following is equivalent to the frictional force during gait?
the ground reaction force in the x- direction
What is the correct symbol for angular position?
theta
True or False? A change in velocity causes an acceleration.
true
True or False? A steeper slope on a position-time curve represents a higher velocity.
true
True or False? All other things being equal, it would be easier to lift and drag an object across the floor than it would be to push it across the floor.
true
True or False? Assuming the same velocity of take-off, with the exception of a take-off angle of 45°, there are two take-off angles that will give an identical range.
true
True or False? Both radians per second and degrees per second are measures of angular velocity.
true
True or False? Displacement is a vector.
true
True or False? For a multi-body system, the location of the center of mass is not fixed.
true
True or False? Force is equal to the change in linear momentum over the change in time.
true
True or False? If a body starts with zero velocity and ends with zero velocity, then the area under the positive acceleration curve must be equal to the area under the negative acceleration curve.
true
True or False? In terms of movement, a force that pushes or pulls in the same direction will have the same effect.
true
True or False? In the horizontal direction, the ground reaction force is the effective force.
true
True or False? The cutting maneuver requires a decrease in momentum in the original direction of travel and an increase in momentum in the new direction of travel.
true
True or False? The negative sign in momentum indicates direction.
true
True or False? The sign of momentum is always in the direction of travel.
true
True or False? The sign of the angular velocity vector is always in the direction of the rotation.
true
True or False? The sign of the velocity vector is always in the direction of the displacement vector.
true
True or False? The velocity of a runner as he crosses the finish line is an example of instantaneous velocity.
true
True or False? Whenever there is a change in direction, the velocity will be zero at the instant the direction changes.
true
true or false? if a body starts with a zero velocity and ends with zero velocity, then the total change in momentum is zero
true