Section 1 (answers may vary) 1. The functional asymmetry ...

Section 1 (answers may vary)
1. The functional asymmetry hypothesis, as it relates to able-bodied gait, is that there is a
consistent task discrepancy between the two lower limbs. According to this theory, the nondominant
lower limb contributes more to support, while the dominant lower limb contributes
more toward forward propulsion.
2. At the preferred speed, the results failed to support the functional asymmetry hypothesis as it
relates to able-bodied gait because no bilateral difference existed between sample means for
vertical or propulsive impulses. Dominant-limb propulsive impulse, however, was 7% greater
than non-dominant limb propulsive impulse at the fast speed.
Section 2
1. (2 points)A 100-kg running back runs with a velocity of 6 m/s towards a stationary 95-kg
defensive back. After the running back collides with the defensive back, what will be the
new combined velocity assuming momentum is conserved and that it is an inelastic
collision
Using the equation m 1 v 1 + m 2 v 2 = (m 1 + m 2 )v 1,2
100 * 6 + 95*0 = (100 + 95)v 1,2
V 1,2 = 3.08m/s
2. (2 points) A 92-kg receiver running at 8 m/s catches a pass across the middle and is
immediately brought to a stop during a collision with a safety that lasts 0.6 seconds. How
much force did the receiver experience
Knowing that F = m*a; and a = ∆v / ∆ t; we know that F = m * ∆v / ∆ t
So, F = 92 * 0 – 8 / 0.6 – 0
F = 1226.67 N
3. (2 points)Beginning with a vertical velocity of zero, a high-jumper pushes off from the
ground for 0.3 seconds and leaves the ground with a vertical velocity of 7 m/s. The jump
caused a vertical ground reaction force of 1822.7 N. Based on your understanding of
ground reaction forces, what is the mass(kg) of the jumper (round to nearest whole
number)
We know that F * ∆ t = m * ∆v

Because body weight is also a vertical force, it too needs to be a part of the equation.
Meaning the sum of the forces is the ground reaction force (GRF) plus the person’s body
weight.
So, ((1822.7 + m(-9.81)) * 0.3 = m * 7
Solving for m, we get
546.81 + -2.943m = 7m
546.81 = 9.943m
m = 55 kg