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Homework Statement:
- I need to find the static and kinetic coefficient of a desk for a physics lab. we have pulleys, string, a scale, a "car" and a few other things. How would I find the force of friction?
Relevant Equations:
- .
no idea
I guess the desk and the floor.Friction involves two surfaces. What are they? Or do you mean rolling resistance?
The "scale" is as in a weighing scale?
What other things?
Which of all the items you listed can directly measure a force?I guess the desk and the floor.
scale is for weighing yes. things that can be used for weight (like paper, beads etc.), measuring tape and i think thats it but we are allowed to bring anything else we want.
nothing? there's a way for sure i just cant think of anything. does anything come to mind?Which of all the items you listed can directly measure a force?
Please do not provide answers so early. Try nudging a little first. The student must be encouraged to think.If your 'scale' can measure tension in a string, just attach it to object(s) and pull
by scale i mean bathroom scaleIf your 'scale' can measure tension in a string, just attach it to object(s) and pull - take reading at the point where the object(s) just begin to move. Alternatively increase slope of surface till object just begins to slide - then ##μ_s=tan(θ) ## if I remember correctly. I can't quite see how to do kinetic friction but I'd guess you will need some kind of 'ticker timer' experiment whereby the object(s) are pulled along the table surface by a falling weight of known value. You should be able to calculate coefficient of kinetic friction if you can obtain a value for the acceleration of falling mass and/or mass sliding on the table.
how would my bathroom scale measure the tension in stringPlease do not provide answers so early. Try nudging a little first. The student must be encouraged to think.
Doesn't that measure force?by scale i mean bathroom scale
It can measure the force provided by the weight of a mass. How could you use that weight?how would my bathroom scale measure the tension in string
force of gravity. i need force of frictionDoesn't that measure force?
weight is equal to force of gravity...It can measure the force provided by the weight of a mass. How could you use that weight?
How could you use the weight of the mass?force of gravity. i need force of friction
weight is equal to force of gravity...
i could get the mass from the weight...
thats all i can think of
i would need to get the desk to start movingWhat do you need the desk to do if you are going to find the maximum static frictional force it has from the floor?
would the weight which equals to force of gravity be equal to force Newton which is the same as force tension?How could you use the weight of the mass?
If you use weight in the right way, yes.would the weight which equals to force of gravity be equal to force Newton which is the same as force tension?
If you use weight in the right way, yes.
Gravitational force is horizontal. What direction do you need the force on the desk? How can you arrange that?
Right. What would your procedure be to find the static frictional force?View attachment 241779
it would look like that (ignore the masses labelled)