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 0.430 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. What is the acceleration of a 2.00 gram drop of blood in the fingertips at the bottom of the swing? Find the force that the blood vessel must exert on the drop of blood in part (a). What force would the blood vessel exert if the arm were not swinging?

Explanation / Answer

Angular velocity = angle/t = 45*3.14/180*0.43 = 1.82rad/s

At the bottom of the swing = Force = m?2r + mg

r = 70 cm = 0.7 m

Acceleration = Force/m = w2r + g = 12.13 m/s2

Force when the arm is swinging = m*a = 2,00*10-3*12.13= 24.26 *10-3 N = 24.26mN

Force When the arm is not swinging = mg = 2.0*10-3*9.81 = 19.62*10-3 N = 19.6 mN

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