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Do Now. Complete the following problems under Do Now on your Daily Organizer. A 15 kg object is lifted 7 m in 3 seconds. What is the weight of the object? Why do you need to find weight first? What is the work done on the object? What is the power used to lift the object?.
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Do Now • Complete the following problems under Do Now on your Daily Organizer. • A 15 kg object is lifted 7 m in 3 seconds. • What is the weight of the object? • Why do you need to find weight first? • What is the work done on the object? • What is the power used to lift the object?
Important dates & reminders • Homework Turn-In • First homework of the quarter due Wednesday! • Report Cards on Thursday • Quiz Tomorrow – Work & Power • Tutoring today from 4 – 5 PM! • Tomorrow’s Lab • Bring your rulersand lab composition books! • In-service Friday – NO SCHOOL
When a force causes an object to be displaced (move or change positions). Work
Calculating work W = Fdcosθ • F is the applied force • D is the distance your object was displaced • Θis the angle between your force and displacement • UNITS: Joules (J)
QUICK REVIEW PROBLEMS • What is the work done when a force of 5 N causes an object to move 5 m? • What is the work done when a 2 kg object is lifted 2 m? • What is the work done when an object has a 20 N force applied 45 degrees above the horizontal that causes it to move 5 m?
What is power? • We know that work is when a force causes some displacement. • Work has nothing to do with the amount of time it takes to move that object though • You can change positions very slow or very fast and you wouldn’t know based on work by itself. • Power is the rate that work happens.
Another power equation • You can rework the equation for power to get a new equation. • This shows us that something with a lot of power is both STRONG and FAST.
QUICK REVIEW PROBLEMS • What is the power used when 60 J of work is done an object in 10 seconds? • What is the power used when a force of 5 N is applied to make an object move 8 m in 4 seconds? • What is the power used to lift a 15 kg object 3 m in 10 seconds?
Complete ALL of the problems in your Daily Organizer. Get your answers checked by Ms. Kemal before you move onto the next section. Once finished, you can move onto Puzzle Masters. Independent practice
Be one of the first five people to complete it to win a raffle prize. Must have all work shown for all problems! Puzzle masters