- #1
gameguru
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Problem:
To hoist himself into a tree a 72 Kg man ties one end of a nylon rope of negligible weight around his waist and throws the other end over a branch of the tree. He then pulls downward on the free end of the rope with a force of 358N. Neglect any friction between the rope and the branch and determine the accleration.
Solution
The only force we need concern ourselves with seems to be the vertical motion. A free body diagram shows a downward force of mg, the rope the man pulls on (T1) and an upward force that the rope exerts on the man based on Newtons 3rd law (T2). My dilema is that if the man pulls on the rope, T1, then doesn't part of his weight (mg)get distributed to the force of T1 since they are both in the same direction. Once the man is off the ground then the full downward force would = T1 + mg. Since no friction occurs between the rope and the branch, the sum of the forces T1,mg would = T2.
Sum of all forces = T2 = ma and solving for a= T2/m. Is this the right approach or am I missing something?.
To hoist himself into a tree a 72 Kg man ties one end of a nylon rope of negligible weight around his waist and throws the other end over a branch of the tree. He then pulls downward on the free end of the rope with a force of 358N. Neglect any friction between the rope and the branch and determine the accleration.
Solution
The only force we need concern ourselves with seems to be the vertical motion. A free body diagram shows a downward force of mg, the rope the man pulls on (T1) and an upward force that the rope exerts on the man based on Newtons 3rd law (T2). My dilema is that if the man pulls on the rope, T1, then doesn't part of his weight (mg)get distributed to the force of T1 since they are both in the same direction. Once the man is off the ground then the full downward force would = T1 + mg. Since no friction occurs between the rope and the branch, the sum of the forces T1,mg would = T2.
Sum of all forces = T2 = ma and solving for a= T2/m. Is this the right approach or am I missing something?.
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