Florida Atlantic University - PHY 2048LLab Report 6: Experiment 6 Collision. Verify energy conservation law when the potential energy of a ball is converted to its kinetic energy and study elastic and inelastic collisions between two balls.

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PHY 2048L Lab Report 6: Lab Report: Experiment 6 Collision Purpose Verify energy conservation law when the potential energy of a ball is converted to its kinetic energy and study elastic and in... elastic collisions between two balls. Theory In this experiment, we use two identical steel balls, with same mass and diameter that are suspended by two massless, non-stretchable strings (massstring << massball). The two balls were separated at their equilibrium (vertical) position, meaning that they were each at their own equilibrium position and barely touching each other. The level at which this occurred represents the reference point for gravitational potential energy (U), meaning that both balls had zero potential energy at this point: U1B= U2B= 0. The ball on the right was designated Ball 1, and the ball on the left was designated Ball 2. When ball one was pulled from its equilibrium position to a certain height h above the guide bar, it gained a potential energy U1A = mgh. Once the ball #1 is release, it gains a maximum velocity v1, therefore a maximum kinetic energy K=1/2m⃗v_1^2 and a maximum linear momentum P1=mv1 just before it hits ball #2. V1 direction is to the left and its magnitude is given by the law of conservation of energy: Before collision ball #2 is at rest, meaning that v2 = 0, therefore P2=0 and K2=0 Consider balls 1 and 2 as a system that has the following total momentum and kinetic energies before colliding: Elastic collision If both the momentum and kinetic energy of the two-ball system are conserved before and after collision, then it is called an elastic collision Pbefore =Pafter Kbefore = Kafter Inelastic collision It is when the momentum but not the kinetic energy of the two ball system is conserved before and after collision Discussion and Conclusion The total energy of the ball at position A (mgh) was 0.172J and the energy just before collision (½mv2) was 0.110 J with a 36.05% difference between the two. Due to the Law of Conservation of Energy, the total energy is conserved. However, this high %error is likely due to an error in the measurement of the height at positions A and B or systematic error in the alignment of the colliding balls. This could have led to incorrect values for height and/or velocity; therefore causing this may have caused the unusually large differences in total energy values or errors in later calculations of momentum or kinetic energy. Questions and exercises hA < h0 because when the ball is held at arm’s length from the boy, it has a potential energy. However, once the ball is dropped, it would immediately lose potential energy and star gaining kinetic energy. hb >>h0 because the energy of the biggest ball that is further down travels upward and transfer its energy to the next ball and so on, until it reaches the top ball. [Show More]

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