- Question A Certain Coiled Wire With Uneven Windings Has The Property That To Stretch It An Amounts From Its Relaxed Len 1 (399.54 KiB) Viewed 26 times
Question: A certain coiled wire with uneven windings has the property that to stretch it an amounts from its relaxed length requires a force that is given by F = bs³, so its behaviour is different from a normal spring. You suspend this device vertically, and its unstretched length is 25 cm. (a) You hang a mass of 18 g from the device, and you observe that the length is now 29 cm. What is b, including units? (b) Which of the following were needed in your analysis in part (a)? (1) The Momentum Principle, (2) The fact that the gravitational force acting on an object near the Earth's surface is approximately mg, (3) The force law for an ordinary spring (F = ks), (4) The rate of change of momentum being zero (c) Next you take hold of the hanging 18 g mass and throw it straight downward, releasing it when the length of the device is 33 cm and the speed of the mass is 5 m/s. After a very short time, 0.0001 s later, what is the stretch of the device, and what was the change in the speed of the mass (including the correct sign of the change) during this short time interval? It helps enormously to draw a diagram showing the forces that act on the mass after it leaves your hand.