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1. 7A . Contrast situations where work is done with different amounts of force to situations where no work is done . Copy everything in the red box! This is the 7A TEKS. What is work?. 2. Work happens when a force moves an object a distance in the same direction of the applied force.
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1 7A Contrast situations where work is done with different amounts of force to situations where no work is done Copy everything in the red box! This is the 7A TEKS
What is work? 2 Work happens when a force moves an object a distance in the same direction of the applied force Copy everything in the blue box! http://www.youtube.com/watch?v=O88BvvKotFo
Two girls are pulling a wagon from the pumpkin patch to their car to load the pumpkin. 3 Work or No Work? Pulling a wagon to the car = WORK
A girl is leaning on the lockers! 4 Work or No Work? Leaning on a locker is NO WORK
His car will not start. He is pushing on the car to move it off the road but it is not moving. 5 Work or No Work? Pushing a car that will not move is NOT WORK
Throwing an object. 6 Work or No Work? Throwing an object a distance = WORK
The president is holding a baby. 7 Work or No Work? Holding something is NOT WORK
Two kids are pushing up and down on a see saw. 8 Work or No Work? Pulling or push to raise the see saw is WORK
Which is more work? 9 A young man throws a ball up the hill. The same young man carries the ball up the hill. Which time did he do more work on the ball? Throwing the ball is more work than carrying it
Which is more work? 10 First this guy tried to lift the lawnmower into the back of the truck. He did it but he hurt his back in the process The next time he needed to move his lawnmower he decided to use a ramp. His back felt much better! SAME amount of work – the ramp only decreases the force but increases the distance.
Which is more work? 11 At the gym one guy was able to lift the weight 10 cm off the ground before dropping it. Another man was able to lift the same weight 20cm off the ground before dropping it. Who did more work? Two people lifting the same object a different distance can change the amount of work done.
Calculating WORK 12 Work = Force x Distance Write the formula!
Calculating WORK 13 • F = 20 N D= 10M • F = 2N D = OM • F = 15N D = 2M What is true about #2? No work was done because there was no distance Solve the equations above
14 Why do we use simple machines? Simple Machines Simple machines require less force to do work!
Less force! How do simple machines lower the amount of force needed to do work? Spread the force out over a greater distance Changing the direction of the force 16 15 Copy the sentences above for each box
videos! 17-20 Draw a picture from the video clips for boxes 17-20 http://www.youtube.com/watch?v=8hrFBYp5LYs&list=PLx6U15Du_TZKcRbdnJ_O3zjPdTXd2J_Jw