• A roller coaster car (RC) of mass m = 1200 kg (includes passengers) is to be thrust into motion from a height H with a speed of vo = 2 m/s. It is to come down the track and complete a full circle along a vertical loop of radius R = 15m. Calculate the following: 
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• i) the least (minimum) speed the RC must have while traveling along the loop in order to prevent an accident (assuming frictionless conditions)? 
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• ii) how strong will the TRACK have to be at the bottom of the loop?
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• iii) how strong the TRACK have to be at the top of the loop? 
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• iv) the energy transferred by gravity as the RC completes a semi-circle starting from the bottom of the loop to the top of the loop.