stops in .011 meter
average speed during deacceleration = 7.3/2 = 3.65 m/s
so time to stop = .011/3.65 = .00301 second
momentum change = 9.5 * 7.3 = 69.4 kg m/s
so F = d (mv)/dt = 69.4 kg m/s / .00301 s
= 23012 kg m/s^2 or Newtons
Note - I used Newtons original second law which is Force = rate of change of momentum. For constant mass this is F = m a
Severe stresses can be produced in the joints by jogging on hard surfaces or with insufficiently padded shoes.If the downward velocity of the leg is 7.3m/s when the joggers foot hits the ground. If the leg stops in a distance of 1.1 cm. Calculate the force on the ankle joint. The mass of the joggers leg is 9.5 kg
1 answer
1 answer