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Task 4.i 3rd class lever
Posted: February 12th, 2013, 4:16 pm
by Splicerblade
The task states that the 3rd class lever can't touch an object at the beginning or end of the task.
I heard about the idea of the catapult but wouldn't the object touch the lever at the beginning of the task
Can you guys please clarify and give me ideas
Re: gear makeup
Posted: February 15th, 2013, 8:33 am
by Mlane
Our team cut our own gears from plastic.
Re: gear makeup
Posted: February 16th, 2013, 6:40 am
by SALIA
How did you make the gear out of plastic? Did you burn the plastic?
Re: gear makeup
Posted: February 16th, 2013, 5:26 pm
by inluvwyth_WANTED
why plastic?
Re: Task 4.i 3rd class lever
Posted: February 19th, 2013, 10:41 am
by goodcheer
Try to mount the object just above the lever so the lever picks it up as it goes up.
Re: Task 4.i 3rd class lever
Posted: February 20th, 2013, 5:01 pm
by trinitypres
we are still confused regarding with rule that the 3rd class lever "must not touch the object at the beginning or end of this task." our third class lever resembles a crane and raises an object connected by a wire cable that extends off the end of the lever. Is this acceptable?
Re: Gears & Levers Questions
Posted: February 25th, 2013, 10:58 am
by Splicerblade
Has anyone gotten a clarification on "3rd class lever can't touch an object at the beginning or end of the task"? Please let me know.
Re: Gears & Levers Questions
Posted: February 25th, 2013, 2:29 pm
by inluvwyth_WANTED
Isn't that task the same as last year? So, I assume other teams have figured that one out?
Re: Gears & Levers Questions
Posted: February 26th, 2013, 6:33 am
by hogger
inluvwyth_WANTED wrote:Isn't that task the same as last year? So, I assume other teams have figured that one out?
Not exactly, the difference is this year the object has to be lifted up which I think makes it a lot more challenging.
Re: Task 4.i 3rd class lever
Posted: March 4th, 2013, 8:48 am
by goodcheer
trinitypres wrote:we are still confused regarding with rule that the 3rd class lever "must not touch the object at the beginning or end of this task." our third class lever resembles a crane and raises an object connected by a wire cable that extends off the end of the lever. Is this acceptable?
It depends on location of the fulcrum and effort. The third class lever has the fulcrum at one end, the load at the other end, and the effort somewhere between the two ends. You can make one using a short, thin piece of wood (say 20cm long since you have to lift load 15 cm), put a hinge on one end for the fulcrum, and a small cup on the other end for the load. Attach a string somewhere in the middle; pull the string in upward direction and the lever rises. Position the load above the cup so the lever will pick it up as it rises and releases it when it gets in the vertical position. We didn't use this task last year, but it turns out to be a good, consistent step. Try it.
Also, when the rule states the object is to be lifted 15 cm above where it starts, we take that to mean to a position 15 cm higher measured vertically, not directly above the start position.