Air Puck Circular Motion Problem?
An air puck of mass 0.032 kg is tied to a string and allowed to revolve in a circle of radius 1.5 m on a frictionless horizontal surface. The other end of the string passes through a hole in the center of the surface, and a mass of 1.7 kg is tied to it, as shown. The suspended mass remains in equilibrium while the puck revolves on the surface. What is the magnitude of the force that maintains circular motion acting on the puck? The acceleration due to gravity is 9.81 m/s 2 . Answer in units of N.
The force is the weight of the suspended mass. F = 1.7 * 9.81 = 16.677 N This is the centripetal force. Fc = m * v^2 ÷ r 16.677 = 0.032 * v^2 ÷ 1.5 v^2 = 25.0155 ÷ 0.032 v = √(25.0155 ÷ 0.032) The velocity is approximately 28 m/s.
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