- Page 2 1 The Head Of A Bolt Is Being Held Between Two Fingers And The Person Is Attempting To Screw It Into A Threaded 1 (169.72 KiB) Viewed 30 times
bolt by the finger and thumb.
b) Since this is a quasi-static static problem detail what
forces additional should be considered.
c) Calculate the torques that the finger and thumb are
applying to the head of the bolt, and hence calculate the total
torque being applied by the hand to the bolt.
d) The person turns the bolt by one turn so the location of the
thumband index finger are now 𝑟⃗t +
𝑝⃗ and r⃗i +⃗p⃗ where
Recalculate the torques on the thumb and finger as well as the
total torque applied by the hand and comment on your results.
e) Explain the reasons for any remaining torque on the bolt
while it is in the threaded hole.
f) Considering the bolt when it is held in space by the head
with just the finger and thumb and with the shaft horizontal. How
is the torque due to the mass of the bold countered by the fingers?
You can consider forces due to gravity to operate on either
the x-axis or the y-axis.
Page 2 1. The head of a bolt is being held between two fingers and the person is attempting to screw it into a threaded hole which is aligned with the Z-axis of the coordinate frame. At a particular instance the forces on the head of the bolt from the index finger f; and thumb F1 are: fi=[fx fy fz]" fi=[-fx -fy fz]" T and the finger and thumb pads are located at: ři = [rx 0 0]" 7; =[-rx 0 0] a) Calculate the forces being applied to the head of the bolt by the finger and thumb. (2 marks) b) Since this is a quasi-static static problem detail what forces additional should be considered. (3 marks) c) Calculate the torques that the finger and thumb are applying to the head of the bolt, and hence calculate the total torque being applied by the hand to the bolt. (4 marks)
Page 3 d) The person turns the bolt by one turn so the location of the thumb and index finger are now ř, + p and ti+P where P = [o o pz]" Recalculate the torques on the thumb and finger as well as the total torque applied by the hand and comment on your results. (6 marks) e) Explain the reasons for any remaining torque on the bolt while it is in the threaded hole. (2 marks) f) Considering the bolt when it is held in space by the head with just the finger and thumb and with the shaft horizontal. How is the torque due to the mass of the bold countered by the fingers? You can consider forces due to gravity to operate on either the x-axis or the y-axis. (3 marks)