People (especially the elderly) who are prone to falling can wear hip pads to cushion the impact on their hip from a fall. Experiments have shown that if the speed at impact can be reduced to 1.3 m/s or less, the hip will usually not fracture. Let us investigate the worst-case scenario in which a 55-kg person completely loses her footing (such as on icy pavement) and falls a distance of 1.0 m, the distance from her hip to the ground. We shall assume that the person’s entire body has the same acceleration, which, in reality, would not quite be true.

(a) With what speed does her hip reach the ground?

(b) A typical hip pad can reduce the person’s speed to over a distance of 2.0 cm. Find the acceleration (assumed to 1.3 m/s be constant) of this person’s hip while she is slowing down and the force the pad exerts on it.

(c) The force in part (b) is very large. To see whether it is likely to cause injury, calculate how long it lasts?