12+Phylets+AR

Lab 12 Physlets Illustration 8.1 When a constant force is applied the change in momentum is the same, regardless of the mass of the object to which the force is applied. The final velocity would change, but the change in momentum would not change because force is equal to the rate of change of momentum. A force applied over a longer period of time causes a greater change in momentum that a force applied over a shorter period of time because impulse is the area under a force vs. time curve. The greater the time over which the force is exerted, the greater the area and the impulse. Illustration 8.2 A change in mass does not affect the change in momentum of an object, but it does effect the change in kinetic energy of an object. The kinetic energy would be equal to the work done when a force is applied to an object at a height of zero. If the mass is larger, then its acceleration is less because force= mass x acceleration. If the acceleration is less, then the distance is less. If the distance traveled is less, then the work is less since work = force x distance. Since the work equals the kinetic energy, then the kinetic energy decreases when the mass increases. Also, when the mass gets greater, the area under the Fcos theta vs. time curve decreases. Therefore, the kinetic energy decreases. Also, if you increase the time in which the force is exerted, the kinetic energy increases because the x distance would also increase. Illustration 8.3 A hard interaction is when the acceleration is large and the interaction is short range. Regardless of whether the collision is considered soft or hard, the law of conservation of momentum still applies, as long as no external forces are applied. If the sum of the two forces is zero, then dp/dt equals zero. The change in momentum over time would be zero. Therefore, the sum of the two impulses would be zero. Also, soft collisions deflect a number of small particles.