PROBLEM SOLVING STRATEGY 25.1 Conservation of energy in charge interactions Learning Goal: MODEL: Check whether there are any dissipative forces that would prevent the mechanical energy from being conserved. To practice Problem-Solving Strategy 25.1 for charge interaction problems. VISUALIZE: Draw a before-and-after pictorial representation. Define symbols that will be used in the problem, list known values, and identify what you are trying to find. A proton and an alpha particle are momentarily at SOLVE: The mathematical representation is based on the law of conservation of mechanical energy: rest at a distance r from each other. They then begin to move apart. Find the speed of the proton Ki + qVi = Ki+ qVi. by the time the distance between the proton and the alpha particle doubles. Is the electric potential given in the problem statement? If not, you'll need to use a known potential, such as that of a point charge, or calculate the potential using the procedure given in Problem-Solving Strategy 25.2. . Ky and Kj are the sums of kinetic energies of all moving particles. Both particles are positively charged. The charge . Some problems may need additional conservation laws, such as conservation of charge or conservation of momentum. and the mass of the proton are, respectively, e and m. The charge and the mass of the alpha particle REVIEW: Check that your result has the correct units and significant figures, is reasonable, and answers the question. are, respectively, 2e and 4m. Model The particles described in this problem interact under the effect of the electric force, which is a conservative force, so the system's mechanical energy is conserved. Visualize Part A Which of the following quantities are unknown? initial separation of the particles O final separation of the particles O initial speed of the proton Ofinal speed of the proton initial speed of the alpha particle O final speed of the alpha particle O mass of the proton O mass of the alpha particle O charge of the proton O charge of the alpha particle Submit Request Answer Solve