L15 Energy: Interactions & Potential
Key Announcement: MS1 is Tomorrow at 8am in computer room
Similar to Knight vs 4 question 9.59. A horizontal spring (k=250 N/m) is compressed 12 cm and a 250g box is placed at the end of the spring. If the coefficient of kinetic friction between the box and the floor is (fk
=0.10), What is the box's maximum speed? (Solve 2 ways...)
Question: Why would this be a difficult problem for Newton's approach?
|Potential, Thermal, Kinetic Energy|
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ΔEsys = ΔK + ΔU + ΔEth = W + Q
- if Q=0 & W=0 → isolated system
- if Q=0 & W=0 & ΔEth=0 → isolated, nondissipative system
F(s) = - dU/ds
Forces: conservative vs non-conservative
- Choose System/Environment
- FBD if needed.
- Solve noting energy
PPT (Ref: Knight Ch 10)