Question

When we walk, our legs alternatively swing forward about the hip joint as a pivot. In this motion the leg is acting approximately as a physical pendulum. Treating the leg as a thin uniform rod of length 0.80 m, find the time it takes for the leg to swing forward.

Answer 1

0.3 seconds

Step-by-step explanation:

When we walk, our legs alternatively swing forward about the hip joint as a pivot. In this motion the leg is acting approximately as a physical pendulum. Treating the leg as a thin uniform rod of length 0.80 m,

To find the time it takes for the leg to swing forward, where g = 9.8 m/s^2

Let's use the simple pendulum formula which says that:

T = 2π( sqrt ( L/g))

T = 2π[sqrt (0.8/9.8)]

T = 2π × 0.082

T = 0.5129

For the leg to swing forward only, the number of complete oscillations will be half.

Period T = time t ÷ number of complete oscillations. That is,

T = t ÷ 1/2

0.5129 = t ÷ 1/2

t = 0.5129 × 1/2

Time t = 0.256 seconds.

Therefore, the time it takes for the leg to swing forward is 0.3 seconds approximately