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petern

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**[SOLVED] Work and Energy Problems**

I have a few work and energy problems I don't understand at all. Please help.

While traveling to school at 27 m/s your car runs out of gas 15 km from the nearest gas station. If the station is 16 m above your current elevation, how fast will the car be going when it reaches the gas station? Ignore friction. Answer 20.4 m/s. Problems must solved using energy principles.

There's only kinetic energy so I would use K = 1/2 mv^2. After that, I don't know what to do.

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A lead ball is traveling at 275 m/s when it strikes a stell plate and comes to a stop. If all its kinetic energy is converted into heat and none of the energy leaves the bullet, what is the bullet's change in temperature? (C = 125 J/ kg * k). Answer: 302.5 degrees C.

I tried using the equation Q = mcT but there no information on either initial or final temperature so I don't know what to do. I tried setting U = K but height's not given.

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A 1.5 kg bass is hooked by a fisherman. The fisherman plays the bass by allowing the fish to swim off 2.1 m/s before braking his reel and stopping the bass in 37 cm. How much tension is exerted on the line? Assume the fish is neutrally buoyant. Answer: 8.94 N

I have no clue on this problem. All I know is that I have to use k = 1/2 mv^2 because it involves velocity.

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