Use conservation of energy, find out velocity, then find distance?

AI Thread Summary
In a collision between two railroad cars, each weighing 7650 kg and traveling at 95 km/h, all kinetic energy is converted into thermal energy, which is essentially heat produced during the impact. To calculate the thermal energy, one must use the conservation of energy principle, equating the initial kinetic energy to the thermal energy generated. For a ski sliding down a 22-degree incline, the potential energy change should be equated to the frictional force times the distance traveled on a level surface, factoring in the coefficient of friction. It's important to note that the frictional force differs on the incline compared to the level ground, and finding velocity is not necessary for this calculation. Understanding these principles will help in solving the problems effectively.
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1. Two railroad cars, each of mass 7650kg and traveling 95km/h in opposite directions, collide head-on and come to rest. How much thermal energy is produced in this collision?
Here does the thermal energy mean like to find friction? I used the conservation of energy formula, but it didn't work out. I don't really know what thermal energy is.
2. A ski starts from rest and slides down a 22 degrees incline 75 m long. If the snow is level at the foot of the incline and has coefficient of friction 0.09, how far will the ski travel along the level?
Then, i think i also need to use conservation of energy, find out velocity, then find distance?

Hope you can give me some hint, thank you.
 
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1) All of the kinetic energy in the railroad cars went 'somewhere'. Ultimately, it went into thermal energy. Thermal energy is heat. 2) Yes, conservation of energy. Find the potential energy change and equate it to frictional force times distance. Note: frictional force is different on the incline than on the level slope. You don't need to find velocity. Those are hints. Now get started.
 
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but how do I find the thermal energy??
 
MIA6 said:
but how do I find the thermal energy??

Dick said:
1) All of the kinetic energy in the railroad cars went 'somewhere'. Ultimately, it went into thermal energy. Thermal energy is heat.


that is how to find it. All of the kinetic energy was converted into thermal(heat) energy.
E_k= ?
 
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