1. three 10,000kg ore cars are held at rest on a 30degree incline on a mine railway using a cable that is parrallel to the incline. The cable is observed to strech 15cm just before the coupling between to lower two cards creaks, detaching the lowest car. Assuming the cable obeys Hook's Law. Find a) the frequency and b) the amplitude of the resulting oscillations of the two remainin cars(adsbygoogle = window.adsbygoogle || []).push({});

-for part a i tried using Fnet= -kx, Fnet being the mass of the 3 cards times gravity times ( sin30 times .15m ) and solving for k, and then puttin k into the formula f = (1/2pi)(sqrt k/m ) i dont know if this is right..

-for part b i dont know how to find the amplitude because in all the equations there are 2 uknowns and i dont know how to solve for the amplitude

4. A 2200lb car carrying four 180lb people drives over a rough "washboard" dirt road with corrugations 13ft apart. The car bounces with maximum amplitude when its speed hits 10mi/h. The car now stops and the four people get out. By how much does the car rise on its suspensions owing to this decrease in weight?

-i know we have to use the mass of the people not the weight, but i dont understand how we use all the information to find how much it rises

5. A small mass with m = 100 grams is attached to a vertical string of length l=2m in the earth's gravity. The mass swings back and forth with no loss of energy. The maximum angle from the vertical is 45 degrees. This problem is not simple harmonic motion because the maximum angle of displacement is not small. Find the velocity when the string is vertical, theta = 0. Find the tension in the string at theta = 0. What is the velocity at theta = 0 if you assume simple harmonic motion?

-i know how to calculate the last part when we assume it is simple harmonic, but how do you find the other stuff if it ISNT SHM?

would appreciate if someone could help me, these questions seem to have me stuck, thanks

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# Homework Help: Simple harmonic motion problems

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