You're carrying a 3.4-m-long, 21 kg pole to a construction site when you decide to stop for a rest. You place one end of the pole on a fence post and hold the other end of the pole 35 cm from its tip. For the steps and strategies involved in solving a similar problem, you may view a Video Tutor Solution. How much force must you exert to keep the pole motionless in a horizontal position?

Question

Hayden

Physics

17 September, 12:42

You're carrying a 3.4-m-long, 21 kg pole to a construction site when you decide to stop for a rest. You place one end of the pole on a fence post and hold the other end of the pole 35 cm from its tip. For the steps and strategies involved in solving a similar problem, you may view a Video Tutor Solution. How much force must you exert to keep the pole motionless in a horizontal position?

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Answers (1)

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Kendal Garrett · Answer 1

120.2 N

Explanation:

assume g = 9.8 m/sec^2

unit weigh = 22*9.8/340 = 0.634 N/cm

post reaction R = (305*0.634*305-35*0.634*35) / (2*305) = 0.634 (305^2-35^2) / 610 = 95.4 N

F = W-R = 22*9.8-95.4 = 120.2 N