- #1
AmirT
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Hi, I'm a second year Design Engineering student. This year we're having some basic physics class. We're doing projects on potential energy at this moment. I'm having a problem with the following;
The assignment:
The teacher assigned us that only 6 Joules of potential energy may be used to make a contraption move as far as possible, this can be anything, a car, a paper plane, etc..
1. Homework Statement
I connected 5 rubber bands in series with on one side a weight (15 grams), on the other side some duct tape.
The duct tape sticks to the ground while the weight is being tentioned. I let loose of the weight and the whole contraption (including rubber bands and duct tape) shoots away.
I need to get to know the potential energy of a shot.
[/B]
I calculated the spring constant by hanging a bottle of with water (545 grams) to the rubber bands in series, the rubber bands stretched out 25cm (50cm - 25cm)
F= kx
k= F/x
k= 5,5N/0,25
k= 22Nm
[/B]
Then I calculated the PE. This is my ACTUAL PROBLEM, I'm very sceptic about this one because it's seems too little.. (I'm not the best with physics or maths)
PE= 1/2*k*x²
PE= 0,5*22Nm*(0.25m)²
PE= 0,6875 J
A picture of the setup
Is this a realistic/plausible result?
Am I doing this right?
The rubber bands I'm using are the typical office rubber bands.
It would be nice if someone could help me out with this one.Thank you.
The assignment:
The teacher assigned us that only 6 Joules of potential energy may be used to make a contraption move as far as possible, this can be anything, a car, a paper plane, etc..
1. Homework Statement
I connected 5 rubber bands in series with on one side a weight (15 grams), on the other side some duct tape.
The duct tape sticks to the ground while the weight is being tentioned. I let loose of the weight and the whole contraption (including rubber bands and duct tape) shoots away.
I need to get to know the potential energy of a shot.
Homework Equations
[/B]
I calculated the spring constant by hanging a bottle of with water (545 grams) to the rubber bands in series, the rubber bands stretched out 25cm (50cm - 25cm)
F= kx
k= F/x
k= 5,5N/0,25
k= 22Nm
The Attempt at a Solution
[/B]
Then I calculated the PE. This is my ACTUAL PROBLEM, I'm very sceptic about this one because it's seems too little.. (I'm not the best with physics or maths)
PE= 1/2*k*x²
PE= 0,5*22Nm*(0.25m)²
PE= 0,6875 J
A picture of the setup
Am I doing this right?
The rubber bands I'm using are the typical office rubber bands.
It would be nice if someone could help me out with this one.Thank you.
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