While a person is walking, his arms swing through approximately a 45.0 angle in

Question

While a person is walking, his arms swing through approximately a 45.0 angle in 0.530 s . As a reasonable approximation, we can assume that the arm moves with constant speed during each swing. A typical arm is 70.0 cm long, measured from the shoulder joint.

a.) What is the acceleration of a 1.70 gram drop of blood in the fingertips at the bottom of the swing?

b.)Find the force that the blood vessel must exert on the drop of blood in part (a).

c.)What force would the blood vessel exert if the arm were not swinging?

Explanation / Answer

a)

What is the acceleration of a 1.70 gram drop of blood in the fingertips at the bottom of the swing is given by

a =w2*r

Where r is radius r =0.70m and w is angualr frequency w =45*2pi/180*0.530 =282.6/95.4=2.962rad/s

Now acceleration (a) =w2*r =(2.962)2*(0.70) =6.14m/s2

b)the force that the blood vessel must exert on the drop of blood in part (a) is given by

Fg =mg =1.70*10-3*9.81 =16.67*10-3N =0.01667N

Fc =mw2r =0.0104N

Now the force exerted on the blood vessel is Fg+Fc =0.01667+0.0104 =0.0271N in the upward direction

c)

If the arm were not swinging then froce exrted is Fg =0.01667N in the upward direction

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