Question

An Olympic runner leaps over a hurdle. The acceleration of gravity is 9.81 m/s2 . If the runner’s initial vertical speed is 2.0 m/s, how much will the runner’s center of mass be raised during the jump?

Answer 1

Consider the upward direction of motion as positive and downward direction of motion as negative.

a = acceleration due to gravity in downward direction = - 9.81 $\frac{m}{s^{2}}$

v₀ = initial velocity of runner in upward direction = 2.0 $\frac{m}{s}$

v = final velocity of runner at the highest point = 0 $\frac{m}{s}$

x = distance by which center of mass of runner rise = ?

Using the kinematics

v² = v²₀ + 2 a x

inserting the values

0² = 2² + 2 (- 9.81) x

x = 0.204 m