View Full Version : A 0.3 kg ball is attached to a string that is 50 cm in length, and completes 2 circle
amos14
Feb 14, 2012, 04:34 PM
a 0.3 kg ball is attached to a string that is 50 cm in length, and completes 2 circles every second.Find the tension required to whirl the ball with the given constriants and also find the angle theta?
jcaron2
Feb 14, 2012, 08:52 PM
Sounds like you're missing a diagram. Can you describe what you mean by the angle theta?
ebaines
Feb 15, 2012, 06:59 AM
Consider the sum of forces acting in the vertical direction:
T \cos \theta - mg = 0
.
where \theta = angle of the rope to the vertical.
For the horizontal direction the horizontal component of the rope's tension must equal the ball's mass times its centripedal acceleration:
T \sin \theta = m\omega^2 R
R is the radius of the circle traced by the ball: R= L \sin \theta. You can find \omega (rotational velocity) from the period of rotation:
\omega = \frac 1 {2 \pi (0.5s)} = \frac 1 {\pi} s^{-1}
So now you have two equation in two unknowns: \theta and T. Let us know what you get for an answer and we'll check it for you.