Question

A rail gun is a ‘futuristic’ device that uses an electromagnetic coil to launch a magnet by running a current up the coil and creating a magnetic field that exerts an accelerating force on the magnet, which is inside the coil. Starting values: magnet’s mass is 1.00 kg; rail gun length is 3.00 m; gravitational acceleration at Earth's surface is 9.81 m/s2. Take the numbers that make up your birth month and year in the format mmdd (my birthday is October 15, so I would be 1015) and make that value the force, in newtons, exerted on the magnet while inside the coil. Once free of the coil, it only experiences gravitational acceleration and air resistance. Gravitational potential energy change within the coil is negligible. The rail gun uses the force you chose to launch the 1.00 kg magnet straight up. It accelerates upwards while inside the 3.00 m long coil, then continues straight upwards until it stops. Energy is lost to the surroundings due to sound emitted as the magnet is launched (0.01%) and air resistance (~40.0%).
Calculate the following:
(a) The height it reaches if 60.0% of the kinetic energy as it leaves the coil is transformed into gravitational potential energy.
(b) The intensity of the sound heard by an observer 10.0 m away from the rail gun if 0.01% of the kinetic energy is transformed into sound waves, assuming a time of 0.0500 s for the transfer of the sound energy.

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Answer 1