Jogging on hard surfaces with insufficiently padded shoes produces large forces in the feet and legs.
(a) calculate the magnitude of the force needed to stop the downward motion of a jogger’s leg, if his leg has a mass of 13.0 kg, a speed of 6.00 m/s, and stops in a distance of 1.50 cm. (be certain to include the weight of the 75.0-kg jogger’s body.)
(b) compare this force with the weight of the jogger. (74)[os 54] (a)

Part a)

Part b)

force is 21.2 times more than the weight of the person

Explanation:

Part a)

As it is given that the distance after which he stopped is given as

d = 1.50 cm

here finally it stops so final speed is given as

initial speed is given as

now by the equation of kinematics we know that

Now the force on the leg is given as

m = mass of leg = 13 kg

Part b)

Force due to weight of the object

here we know

M = 75.0 kg

Now we know that the ratio of the weight with the force on leg is given as

so force is 21.2 times more than the weight of the person