Answer:
Distance = 6.27 x 10⁻⁴m
Explanation:
The speed just before hitting the ground may be expressed as
v = √2gh, where g is the acceleration due to gravity and h is the height
v = √(2 x 9.81 x 0.4) = 2.8 m/s
Using the work -energy theorem, we know that any work done on the object produces a change of kinetic energy in the object. Hence
Net Work = Final Kinetic Energy - Initial Kinetic Energy
The initial condition is stationary hence the initial Kinetic Energy = 0
Net Work may be written as
Net Work = Force x Distance = Final Kinetic Energy
4 x 10⁵ x d = (1/2) x mass x velocity²
d = {(1/2) x 64 x 2.8²}/(4 x 10⁵) = 6.27 x 10⁻⁴m
6.27 x 10⁻⁴m is the minimum stopping distance to avoid breaking his tibias.
