A train of mass 40 000 kg travelling at 150 mph comes to a stop in a distance of 1 km. The initial velocity of the train is 67 m/s. a) Calculate the initial kinetic energy of the train. Show your working. Give the unit.
b) Calculate the acceleration of the train as it comes to a halt. Show your working. Use the equation:
(final velocity squared) − (initial velocity squared) = 2 x acceleration x distance

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Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)

You are a researcher for a golf club manufacturer. you are given two identical looking cubes of a metal alloy. you are informed that they are made of the exact same material, but one is crystalline, whereas the other is amorphous. it is your job to determine which one is amorphous this one is more stress-resistant and is useful in reinforcing golf clubs. which of the following is the best way to determine which is which? a. determine the density of each cube. the more dense one is the amorphous solid. b. melt both cubes and look for a broader range of melting temperatures. the one that melts over a broader range of temperatures is the amorphous solid. c. determine the density of each cube. the less dense cube is the amorphous solid. d. melt both cubes and measure the range of melting temperatures. the one that melts over a narrower range of temperatures is the amorphous solid.