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In terms of what we have been studying, what important thing does a horse and car have in common?

In terms of what we have been studying, what important thing does a horse and car have in common?. +. POWER!. Let’s Review What We Already Know WORK before we get to POWER. We know that in physics WORK is when a force has moved an object over a certain distance . Example:

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In terms of what we have been studying, what important thing does a horse and car have in common?

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  1. In terms of what we have been studying, what important thing does a horse and car have in common? +

  2. POWER!

  3. Let’s Review What We Already KnowWORK before we get to POWER • We know that in physics WORK is when a force has moved an object over a certain distance. Example: • Pushing on a huge boulder and not moving it vs. picking up a small rock: Which situation is an example of work? Why?

  4. What Do You Think?Write down your answer completely. • There are two cars that weigh the same at the bottom of Eagle Rock Avenue and they both travel to the top. Have they done work? Explain.

  5. What is Power? • Power is WORK per unit of TIME • Example of Power: There are two cars at the bottom of the Eagle Rock Avenue again. They both weigh the same and drive up the hill (so they do the same amount of work)but the sports car climbs the hill faster . Because they are doing the same amount of work, but one is faster we say the faster one has more POWER.

  6. What Do You Think?Write your answer! • You challenge your BFF to a race from one end of the hallway to the other end. (DON’T ACTUALLY DO THIS!). She beats you by a second. (UGH!) Who used more power? How do you know? • Explain how time is related to power.

  7. Horsepower • The term 'horsepower' is largely credited to James Watt, in the late 1700s. Watt was a Scottish engineer who invented a number of improvements to steam engines • Most of Watt's potential clients were using horses, so he soon found that in order to market his engines, he needed to express the power of his engines in terms of how many horses a given engine would replace. • As machines replaced horses, people naturally estimated the POWER of a machine by how many horses it could replace.

  8. Horsepower • Today’s engines are still rated in terms of horsepower. • Horsepower technically is the power needed to raise 550 pounds (say a fully grown male tiger!) a distance of one foot in one second.

  9. Examples of Horsepower

  10. Your Task In this experiment we are going to find out how much horse power you can generate climbing the stairs.

  11. Procedure: • Fill in your hypothesis: I think I can generate _____________ horsepower. • 2. Complete the Lab: • The timer will stand at the top of the stairs and the climber will stand at the resting point at the bottom. • When the timer says GO the climber will run up the stairs. DO NOT SKIP STAIRS • The climber will record the time it took to run up the stairs. 3. Calculate your horse power. (Use the formula on your lab sheet.) 4. Answer the conclusion questions for homework!

  12. Math calculation Sample for after the lab. Data: Use the equation to calculate the amount of horsepower you generated by running up a flight of stairs. (Show your work) Horsepower = w x h 550 x t w = your weight h = height of stairs in feet t = time in seconds Sample DATA Weight = 100 Height of stairs = 6 ft Time to reach the top = 15 seconds 100 lbs X 6 feet 550 X 10 sec 100 x 6 = 600 550 x 10 = 5500 600 divided by 5500 = 0.11 horsepower

  13. Practice ProblemWrite out your work Weight = 100 lb Height = 10 ft Time = 10 seconds

  14. Practice Problem Solution 100lbs x 10ft 550 x 10sec 100 x 10 = 1000 550 x 10 = 5500 1000/5500 = 0.18 horsepower

  15. Power Notes • 1. In terms of what we have been studying, what important thing does a horse and car have in common? • 2. There are two cars that weigh the same at the bottom of eagle rock avenue and they both travel to the top. Have they done work? Explain. • 3. What is the formula for power? • 4. You challenge your BFF to a race from one end of the hallway to the other end. (DON’T ACTUALLY DO THIS!). She beats you by a second. (UGH!) Who used more power? How do you know? • 5. Explain how time is related to power.

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