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BrainMan
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A stuntman swings from the end of a 4 m long rope along the arc of a circle. If his mass is 70 kg, find the tension in the rope required to make him follow his circular path at (a) the beginning of his motion, assuming he starts when the rope is horizontal, (b) at a height of 1.5 above the bottom of the circular arc, and (c) at the bottom of the arc.
(Equation) Fc = mv^2/r
KE= 1/2mv^2
PE = mgy
(Attempt at solution)
Find the total energy of the system
4 m (9.8)(70 kg) = 2744 J
Find the kinetic energy at 1.5 m to find the velocity
70(9.8)(1.5) = 1029
2744 - 1029 = 1715 J
1/2mv^2 = 1715
V= 7 m/s
Find the centripetal force using Fc= mv^2/r
70(49/4)
Fc = 857.5
The correct answer is 1.29 x 10^3 N
(Equation) Fc = mv^2/r
KE= 1/2mv^2
PE = mgy
(Attempt at solution)
Find the total energy of the system
4 m (9.8)(70 kg) = 2744 J
Find the kinetic energy at 1.5 m to find the velocity
70(9.8)(1.5) = 1029
2744 - 1029 = 1715 J
1/2mv^2 = 1715
V= 7 m/s
Find the centripetal force using Fc= mv^2/r
70(49/4)
Fc = 857.5
The correct answer is 1.29 x 10^3 N
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