What type of machine is a scissor? A.S.A.P. help?

Question

What specific type of machine is for each scissors?
Scissors A- top part (open holes)- 3 cm. and the end part 6 cm.
Scissors B- top part (open holes)- 6cm. and the end part 3 cm.
How do you calculate the input force that would need to be applied to each scissors to cut and object of 2N?
How do u find the mechanical advantage?
Is it easy to determine without the calculation?

Answer 1

Jerry P is correct about the description- you could add opposing co-levers or something.

This is a very hard question make no mistake. The answer is NOT 1 newton.

Think about it when you use different scissors like you have described on the same object you have to squeeze harder on one right? = more or less N required

Heres a hint - the amount you squeeze the handle is the input force required. So that is both levers N added. Ultimately the N of both levers at once equals 2N, so the question is what force needs to be applied to the handles to achieve this on the different type of levers.

So when you squeeze you are pushing the lever at an angle from the fulcrum, even though you are squeezing parralell with the way you want the object to be cut.

Picture a line perpendicular to the scissor lever face on both sides, scissors open. Now the Angle from vertical of the fulcrum varies from scissor A to scissor B. Use maths to work this out. Trig! Think of the force as a distance. I wish I had a pen.

Now we know that the force required by both levers at the fulcrum is 1N. So what force is required pushing that one lever at that angle to produce a force of 1N parralell to your squeezing hands. just use algebra and trig.

Mechanical advantage is basically the results of your calculations. The scissors that require the less squeezing have the mechanical advantage.

You can use practical educated guess work without the calculation. ie I recall that when I used stumpy scissors I had to push less hard to cut something than with longer ones. But generally you need the calculation otherwise its just trial and error guesswork

Ask your prof if the sharpness of the blade or the thickness of the blades have been taken into account if you want to be a smartass/ earn brownie points

Good luck

Answer 2

the mechanical advanntage is like any lever except that scissors apply forces from both sides. you would want a force of 2N at the center, but basically thats 1 N up and 1 N down, the scissors dont move up or down when you use them, just think lever arms and u wont be doing much calulations since the force is 1N

Answer 3

It is a pair of levers, with the fulcrum where the blades meet.

Answer 4

http://www.scissors.com