This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Phys 2101 Gabriela González • There is potential energy associated with the work of conservative forces (gravity: U=mgh; springs: U= ½ kx 2 ): Δ U = U f – U i = ¡ W • If the only forces doing work are conservative the sum of kinetic and potential energy is conserved: Δ U + Δ K = 0 U f + K f = U i + K • If there are nonconservative forces, the change in the total energy (potential + kinetic) is equal to the work done by those forces: Δ U + Δ K = W other 2 3 If only conservative forces are in action (gravity, springs, normal forces, tension…) then the mechanical energy , the sum of potential and kinetic energy , is conserved. maximum kinetic = minimum potential minimum kinetic = maximum potential 4 In the figure shown, a single frictionless rollercoaster car of mass m tops the first hill with speed v at height h . How much work does the gravitational force do on the car from that point to (a)point A , (b) point B , and (c) point C ? If the gravitational potential energy of the car–Earth system is taken to be zero at C , what is its value when the car is at (d) B and (e) A ? (f) If mass m were doubled, would the change in the gravitational potential energy of the system between points A and B increase, decrease, or remain the same? 5 The figure shows a ball with mass m = 0.3 kg attached to the end of a thin rod with length L = 0.5 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle....
View
Full
Document
This note was uploaded on 12/01/2011 for the course PHYS 2101 taught by Professor Grouptest during the Fall '07 term at LSU.
 Fall '07
 GROUPTEST
 Physics, Energy, Force, Gravity, Potential Energy, Work

Click to edit the document details