- #1

bssmagik

- 4

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**here's a set of 5 questions: Work and Energy**

## Homework Statement

1. 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.

2. A lead ball is traveling at 275 m/s when it strikes a steel 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?

3. A 637 gram sample of water at 92 C is mixed with 843 grams of water at 27 C. Assume no heat loss to the surroundings. What is the final temperature of the mixture?

4. Tommy throws his car keys straight up into the air from height of 1.5 m above the ground. His keys strike the ground at a speed of 7.7 m/s. Ignoring friction, how fast did Tommy throw his keys?

5. A 1.5 kg bass is hooked by a fisherman. The fisherman plays the bass by allowing the fish to swim off at 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.

## Homework Equations

i know that:

(Clead = 125 J/kg•K)

(Cwater = 4180 J/kgK)

## The Attempt at a Solution

I did all of these in my head/on a calculator, but I'm not sure how any of the equations work or what they are. I've always been able to get the answer without any knowledge of how i did it. Help??

20.8 m/s

302.5 C

54.98 C

5.47 m/s

8.94 N