In a human pyramid in a circus, the entire weight of the

Question

In a human pyramid in a circus, the entire weight of the balanced group is supported by the legs of a performer who is lying on his back (as shown in Fig. 9.5). The combined mass of all the persons performing the act, and the tables, plaques etc. involved is 280 kg. The mass of the performer lying on his back at the bottom of the pyramid is 60 kg. Each thighbone (femur) of this performer has a length of 50 cm and an effective radius of 2.0 cm. Determine the amount by which each thighbone gets compressed under the extra load.

Ankush Patil · Accepted Answer

Total mass of all the performers, tables, plaques etc.= 280 kgMass of the performer= 60 kgMass supported by the legs of the performer at the bottom of the pyramid = 280 – 60 = 220 kgWeight of this supported mass = 220 kg wt. = 220 × 9.8 N = 2156 N.Weight supported by each thighbone of the performer = ½ (2156) N = 1078 N.Young’s modulus for bone is given by Y = 9.4 × 109 N m–2.Length of each thighbone L = 0.5 m the radius of thighbone = 2.0 cmThus the cross-sectional area of the thighbone A= π × (2 × 10-2)2 m2 = 1.26 × 10-3 m2. The compression in each thighbone (∆L) can be computed as ∆L = [(F × L)/(Y × A)] = [(1078 × 0.5)/(9.4 × 109 × 1.26 × 10-3)]= 4.55 × 10-5 m or 4.55 × 10-3 cm.This is a very small change! The fractional decrease in the thighbone is ∆L/L = 0.000091 or 0.0091%.

General Physics> In a human pyramid in a circus, the entir...

Jayant Kumar , 10 Years ago

Ankush Patil

Provide a better Answer & Earn Cool Goodies

LIVE ONLINE CLASSES

Ask a Doubt

moment of inertia of a equilateral triangle about an axis passing through centre and perppendicular to the plane

General Physics

. Because of the rotation of the earth, a plumb bob may not hang exactly along the direction ofthe earth’s gravitational pull (its weight) but deviates slightly from this direction. Calculate thedeviation (a) at 40 latitude, (b) at the poles, and (c) at the equator

General Physics

General Physics

A block is kept on x-y plane at a point (2m,3m). It is pushed with a force of magnitude 10 Ntowards point (5m,7m). The force can be represented as?

General Physics

The phase of particle at t is 70°and another particle is at t is 790° what is wavelength if the distance between two particles is1 m

General Physics

General Physics> In a human pyramid in a circus, the entir...

Jayant Kumar , 10 Years ago

Ankush Patil

Provide a better Answer & Earn Cool Goodies

LIVE ONLINE CLASSES

Ask a Doubt

Other Related Questions on General Physics

moment of inertia of a equilateral triangle about an axis passing through centre and perppendicular to the plane

General Physics

. Because of the rotation of the earth, a plumb bob may not hang exactly along the direction ofthe earth’s gravitational pull (its weight) but deviates slightly from this direction. Calculate thedeviation (a) at 40 latitude, (b) at the poles, and (c) at the equator

General Physics

General Physics

A block is kept on x-y plane at a point (2m,3m). It is pushed with a force of magnitude 10 Ntowards point (5m,7m). The force can be represented as?

General Physics

The phase of particle at t is 70°and another particle is at t is 790° what is wavelength if the distance between two particles is1 m

General Physics