Posted by Angelina on .
A 0.700-kg ball is on the end of a rope that is 0.90 m in length. The ball and rope are attached to a pole and the entire apparatus, including the pole, rotates about the pole's symmetry axis. The rope makes an angle of 70.0° with respect to the vertical as shown. What is the tangential speed of the ball?
physics - Angelina, Friday, February 17, 2012 at 12:00am
I was thinking that it would be .90tan(70)=2.47 m/s^2 but I am wrong so I don't know how to do this...
physics - drwls, Friday, February 17, 2012 at 2:28am
Let the rope tension be T.
T sin70 = M V^2/R
T cos70 = M g
Now, divide the first equation by the second one.
tan70 = V^2/(R*g)
V^2 = (0.90)(9.8)(2.747)= 24.23 m^2/s^2
V = 4.92 m/s
Your answer does not have the dimensions of velocity, and must depend upon g.
physics - Angelina, Friday, February 17, 2012 at 4:34pm
What is the tangential speed of the ball?
thnks but i tried both 24.23m^2/s^2 and 4.92 n neither are right i don't understand whats wrong