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phy An archer pulls her bowstring back 0.360 m by exerting a force that increase

ID: 2117593 • Letter: P

Question

phy

An archer pulls her bowstring back 0.360 m by exerting a force that increases uniformly from zero to 211 N. What is the equivalent spring constant of the bow? How much work does the archer do on the string in drawing the bow? In 1990 Walter Arfeuille of Belgium lifted a 2 8 1 .5 -kg object through a distance of 17.1 cm using only his teeth. How much work was done on the object by Arfeuille in this lift, assuming the object was lifted at constant velocity? What total force was exerted on Arfeuille's teeth during the lift?

Explanation / Answer

1)

a)

K=F/x =211/0.36 =586.11 m

b)

W=(1/2)Kx^2 =(1/2)*586.11*0.36^2 =37.98 J

2)

a)

W=Fd =(mg)d

W=(281.5*9.8)*0.171

W=471.74 J

b)

Ft =F =mg =281.5*9.8

Ft=2758.7 N

Ft =2.7587 KN