A 65kg kid runs at 5.0m/s , grabs a rope, and swings out over a lake. He releases the rope when his velocity is zero. a) what is the angle when he releases the rope? b) What is the tension in the rope just before he releases it? c) What is the maximum tension in the rope?
2006-12-06 06:18:47 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
You left out the length of the rope. this must be known since the rope length is related to the angle of release and to the tension in the rope.
a) Using conservation of energy, when the kid's velocity is zero, all of the kinetic energy from the run will get converted to potential energy against gravity.
Rope length = R
angle of release = a
cos(a)=(R-h)/R
where h is the vertical gain
cos(a)=(R-(v^2/(2*g)))/R
v=5
g=9.81
b) the tension in the rope at release will be zero since there is no angular velocity
c) Maximum tension is at take-off since that will also be maximum angular velocity
F=m*w^2*R
w=v/R
F=m*v^2/R
j
2006-12-08 14:14:23 · answer #1 · answered by odu83 7 · 1⤊ 0⤋