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mot
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"Easy" conceptual energy problem?
Here's the diagram
http://nkkkjkjjjjjjjjjjj.tumblr.com/image/65137695911
A bead slides on a wire, which is in a vertical plane, as shown in the diagram. Gravity acts in the -y direction. The bead starts at A, moving to the right with an initial velocity v. The wire is frictionless between A and D and between F and G, but there is friction between D and F. (For each statement select True, False, Greater than, Less than, Equal to, or Not enough information to tell.
1. The bead's kinetic energy at B is ... its kinetic energy at F
2. Between A and C, there is positive work done on the bead
3. Between D and F, the speed decreases, then increases
4. The speed at C is ... the speed at E
E_g=mgy
E_k=1/2mv^2
The bead's kinetic energy at B is ... its kinetic energy at F: For this is said greater than because, although they are at the same height, all the energy is not conserved because it experiences friction between D and F.
Between A and C, there is positive work done on the bead
I said True because the dispacement is in the same direction as the force of gravity
Between D and F, the speed decreases, then increases
I said true for this one. At D it experiences friction and slows down while moving horizontally, then it starts to go down, so a component of gravity acts to accelerate it. Even if it is still slowing down, it's still speeding up relative to its speed at E.
The speed at C is ... the speed at E
I put not enough info...We don't know how much friction slowed the bead down between D& E compared to how much it "sped up" on that decline between C & D.
But these answers are wrong...can someone help? Thanks so much!
Homework Statement
Here's the diagram
http://nkkkjkjjjjjjjjjjj.tumblr.com/image/65137695911
A bead slides on a wire, which is in a vertical plane, as shown in the diagram. Gravity acts in the -y direction. The bead starts at A, moving to the right with an initial velocity v. The wire is frictionless between A and D and between F and G, but there is friction between D and F. (For each statement select True, False, Greater than, Less than, Equal to, or Not enough information to tell.
1. The bead's kinetic energy at B is ... its kinetic energy at F
2. Between A and C, there is positive work done on the bead
3. Between D and F, the speed decreases, then increases
4. The speed at C is ... the speed at E
Homework Equations
E_g=mgy
E_k=1/2mv^2
The Attempt at a Solution
The bead's kinetic energy at B is ... its kinetic energy at F: For this is said greater than because, although they are at the same height, all the energy is not conserved because it experiences friction between D and F.
Between A and C, there is positive work done on the bead
I said True because the dispacement is in the same direction as the force of gravity
Between D and F, the speed decreases, then increases
I said true for this one. At D it experiences friction and slows down while moving horizontally, then it starts to go down, so a component of gravity acts to accelerate it. Even if it is still slowing down, it's still speeding up relative to its speed at E.
The speed at C is ... the speed at E
I put not enough info...We don't know how much friction slowed the bead down between D& E compared to how much it "sped up" on that decline between C & D.
But these answers are wrong...can someone help? Thanks so much!