Row 1
True or False: At the apex, velocity is zero.
True
True or False: Body segment orientation is the angle between anatomical position (0°) and the position of the body segment that has moved.
False; Joint angle
True or False: Velocity is the inverse of speed.
False
True or False: Vertical and horizontal components act independently of each othe
True
True or False: If the goal is maximum horizontal displacement, the optimal projection angle is 90 degrees.
False; 45 degrees.
What are the 3 factors that influence the projectile trajectory?
1. Angle of projection
2. Projection speed
3. Relative projection height
In the real world, what factors affect a projectile once its airborne?
Gravity & air resistance.
A runner moving at a velocity of 6 m/s increases the velocity to a rate of 10 m/s in a 2 second time interval. What is the rate of acceleration?
a= 2 m/s^2
True or False: Increasing the radius of a rotating body will increase the amount of linear distance travelled by that body.
True
Range of motion at a joint is a measurement of what?
Angular displacement
Marcus decided to run 4 laps around a 400m track, ending in the same location he began.
He finished the 4 laps he ran in 9 minutes. What was his speed?
s= 2.96 m/s
How would you decrease radial acceleration?
decrease the linear velocity or increase the radius of curvature.
Angular ______: sum of all angular changes undergone by a rotating body.
Distance
Angular _______: change in the angular position or orientation of a line segment
Displacement
If the elbow goes through 125° of flexion during a bicep curl, what is the total angular distance during 5 reps?
1250 degrees
Distinguish between Linear acceleration and velocity.
Acceleration: rate of change in linear velocity
Velocity: the rate of change in location/position
Distinguish between Angular distance and displacement.
Distance: sum of all angular changes undergone by a rotating body.
Displacement: change in the angular position or orientation of a line segment.
Distinguish between positive and negative acceleration. Give an example of each.
Positive: increasing angular velocity in positive direction or decreasing angular velocity in the negative direction
- Ex: Launching a rocket.
Negative: decreasing angular velocity in the positive direction or increasing angular velocity in the negative direction.
- Ex: A ball being dropped.
A swimmer crosses a lake that is 0.9 km wide in 30 minutes. What was the average velocity? Can his average speed be calculated?
v = 1.8 km/hr
Cannot calculate the speed because we don’t know the distance.
A volleyball is deflected vertically by a player during a block. The high school gym has a ceiling clearance of 10.5m. If initial velocity of the ball is 14m/s, will the ball hit the ceiling?
d = 9.99 m
The volleyball will not hit the ceiling.
Sherry decides to go on a walk to her favorite park. She begins by heading 600 m east, and then takes a sharp left turn going north for 400 m (90 degrees from her due east position). What was her final displacement with respect to the original trailhead (where she began)?
c= 721.1 meters
A soccer ball is kicked at an angle of 40° with an initial velocity of 10m/s. What are the vertical and horizontal components? How high and how far does the soccer ball go?
Vh = 7.66 m/s
Vv = 6.43 m/s
d= 2.11 m high
dh= 10.03 m far
Two baseballs are consecutively hit by a bat. The first ball is hit 0.2 m from the bat’s axis of rotation, and the second ball is hit 0.4 m from the bat’s axis of rotation. If the angular velocity of the bat was 30 rad/s at the instant both balls were contacted, what was the linear velocity of the bat at the two contact points?
Ball 1: v = (0.2m)(30rad/s) v = 6 m/s
Ball 2: v = (0.4m)(30rad/s) v = 12 m/s
The score was tied 20-20 between the Vikings and the Packers. At the end of the game, the Vikings had an opportunity to kick the winning field goal. The ball was placed 42m from the goalpost. If the ball was kicked with a horizontal component of initial velocity of 19m/s and a flight time of 2.4s, was the kick long enough to make the field goal?
d = 45.6 m
45.6 > 42 so the kick was good!
A windmill-style softball pitcher executes a pitch in 0.65s. If her pitching arm is 0.7m long, what are the magnitudes of the tangential and radial accelerations on the ball just before ball release when ball velocity is 20m/s?
What is the magnitude of the total acceleration on the ball at the release point?
radial acceleration: ar = 571.4 m/s2
tangential acceleration: at = 30.8 m/s2
total acceleration: a = 572.2 m/s2