People (especially the elderly) who are prone to falling can wear hip pads to cu

Question

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 1.30 m/s or less, the hip will usually not fracture. Let us investigate the worst-case scenario, in which a 63.0 kg person completely loses her footing (such as on icy pavement) and falls a distance of 1.00 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. find the force the pad exerts on it. Assume +y downward.

1. A typical hip pad can reduce the person's speed to 1.30 m/s over a distance of 2.00 cm. Find the acceleration (assumed to be constant) of this person's hip while she is slowing down.

Assume +y downward.

2. find the force the pad exerts on it.

Assume +y downward.

Explanation / Answer

1] velocity before striking ground = - sqrt(2gh) = - sqrt(2*9.8*1) = - 4.427 m/s

acceleration = [v^2 - u^2]/2s = [4.427^2 - 1.3^2]/(2*0.02] = 447.7 m/s^2

2.Force exerted by pad = m * a

= 63*447.7 = 28205 N answer

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