1 EXS 387 - BIOMECHANICS Dr. Moran Spring 2007 ANSWERS Solutions for short answers will be provided in Lab Sections 1.) If velocity is constant, then acceleration equals: a.) Not Enough Information b.) Zero c.) Change in Displacement d.) Change in Velocity e.) b and d 2.) The word qualitative means which of the following: a.) Descriptive b.) Non-numerical c.) Numerical d.) None of the above 3.) The typical joint terminology associated with movement in the frontal plane are: a.) Flexion/Extension b.) Plantarflexion/Dorsiflexion c.) Medial/Lateral Rotation d.) Abduction/Adduction 4.) A gymnast performing revolutions around a high bar would be an example of: a.) Rectilinear Motion b.) Curvilinear Motion c.) General Motion d.) Angular Motion e.) b and e 5.) The direction term corresponding with “further from the trunk” would be: a.) Distal b.) Proximal c.) Superior d.) Inferior e.) Medial 6.) For a 2-dimensional kinematic analysis the first step of any analysis should be: a.) Identify the ability of participant b.) Identify the primary plane of motion c.) Identify the means of visualization (i.e. camera) d.) Identify the viewing angle of motion 7.) A runner participates in the Red Dragon Homecoming 5K where the start and finish line are in the exact same location. What kinematic term does the 5K represent? a.) Displacement b.) Distance c.) Acceleration d.) Speed e.) None of the above 8.) It has been shown that when adults are in a rush they will increase walking speed by:2 a.) Increasing stride length ONLY b.) Increasing stride frequency ONLY c.) Increasing BOTH stride frequency and stride length d.) Increasing stride rate ONLY 9.) At what given time point(s) does 0 displacement occur: a.) T1 b.) T1 and T4 and T2 c.) T4 d.) T2 e.) None of the above 10.) At what given time points is the velocity most positive? a.) T1 b.) T3 c.) T5 d.) T7 e.) None of the above 11.) At what given time point(s) is the displacement most negative? a.) T1 b.) T5 and T7 c.) T3 d.) T7 e.) None of the above 12.) At what given time point is the velocity changing directions? a.) T1 b.) T2 c.) T3 d.) T4 e.) None of the above 13.) Which of the following does not influence the trajectory of projectile motion? a.) Projection Release Height b.) Projection Speed c.) Incidence Angle d.) Projection Angle 14.) In reality, once a projectile is airborne it will be affected by which of the following: a.) Gravity b.) Air Resistance c.) Both a and b d.) None of the above 15.) At the vertical peak of a projectile’s trajectory, the vertical velocity will equal: a.) Depends on the circumstances b.) Zero c.) Negative d.) Positive e.) None of the above 16.) What is the terminology of an angle that is measured from the thigh segment and the ground horizontal: a.) Relative Angle b.) Absolute Angle c.) Inclination Angle d.) Both b and c e.) None of the above3 17.) A figure skater performs a 2 ½ revolution spin. What was his/her total angular displacement? a.) Can’t determine – need to know axis of rotation b.) 2 ½ c.) 1 d.) ½ e.) Zero 18.) What is one reason a 3-iron will drive a ball further than a 7-iron in golf? a.) Shaft of a 3-iron is longer than a 7-iron b.) Shaft of a 3-iron is shorter than a 7-iron c.) It is easier to swing a 7-iron faster d.) A 3-iron is easier to control at ball impact 19.) A short-track speed skater is performing a sharp turn at a constant speed. What inference(s) is correct? a.) Angular displacement = Angular Distance b.) Velocity is constant c.) Acceleration is ZERO d.) Acceleration is non-ZERO e.) None of the above 20.) The acceleration of a body in angular motion can be decomposed in which of the following: a.) Radial and tangential acceleration terms b.) Horizontal and vertical acceleration terms c.) Centripetal and centrifugal acceleration terms d.) Horizontal and vertical velocity terms SHORT COMPUTATION ANSWERS 1a.) 3.18 m/s 1b.) 3.18 m/s (neglecting air resistance) 1c.) 1.69 m/s 1d.) 0.146 m 1e.) 0.17 s 2.) 51.54 deg 3a.) 17.86 rad/s 3b.) ball elasticity, directness of club face/ball contact 4a.) 3.33 m/s2 4b.) -0.5 m/s2 5a.) Johnson – 10.17 m/s; Lewis – 10.14 m/s 5b.) Johnson reached 80m first but Lewis had a faster velocity at the 80m mark (11.76 m/s to 11.30 m/s). You find those the 80m velocity by using the 70m and 90m split