# Help please!! Tension problem!!An air puck of mass 0.108 kg is tied to a string and allowed to revolve in a circle of radius 0.96 m on a horizontal, frictionless table. The other end of the string...

Help please!! Tension problem!!

An air puck of mass 0.108 kg is tied to a string and allowed to revolve in a circle of radius 0.96 m on a horizontal, frictionless table. The other end of the string passes through a hole in the center of the table and a mass of 1.19 kg is tied to it. The suspended mass remains in equilibrium while the puck revolves. What is the tension in the string? Answer in units of N

*The acceleration of gravity is 9.8 m/s2 .*

### 1 Answer | Add Yours

The air puck of mass 0.108 kg is tied to a string and allowed to revolve in a circle of radius 0.96 m on a horizontal, frictionless table. The other end of the string passes through a hole in the center of the table and a mass of 1.19 kg is tied to it. The suspended mass remains in equilibrium while the puck revolves.

As the puck revolves in a circle with a constant acceleration there is an outward force acting on it equal to m*v^2/r. This force pulls the string upwards. But there is a counter balancing force of 1.19*9.8 N due to the mass that is tied to the other end of the string.

At equilibrium the string is pulled downwards by a force equal to 1.19*9.8 and upwards by an equal force. The tension in the string due to these forces is 1.19*9.8*2 = 23.324 N.

**Sources:**