1. Give examples of direct measurements in LR No.3 .What determines the error of direct measurements? 2. Formulate the law of conservation of momentum and the conditions for its fulfillment for open-loop systems. Is the momentum of the projectile retained after firing in operation No 3? Justify the answer. 3. Formulate the law of change of mechanical energy. How and why does the energy of the fly- wheel-load system change during movement?

1. Direct measurements in LR No. 3 refer to measurements where the quantity being measured is directly observed or read from a measuring instrument. Examples include measuring the length of an object using a ruler, measuring the volume of a liquid using a graduated cylinder, and measuring the mass of an object using a balance. The error of direct measurements is determined by factors such as the precision of the measuring instrument, the skill of the person taking the measurement, and any external influences that may affect the measurement.<br /><br />2. The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it. In the context of open-loop systems, the law of conservation of momentum can be formulated as follows: The total momentum of the system before an event (such as a collision or explosion) is equal to the total momentum of the system after the event, provided no external forces are involved. The conditions for the fulfillment of the law of conservation of momentum are that the system is closed (no mass enters or leaves the system) and no external forces act on the system.<br /><br />In operation No. 3, the momentum of the projectile is not retained after firing. This is because the projectile experiences external forces, such as gravity and air resistance, which cause it to deviate from its initial trajectory and change its momentum.<br /><br />3. The law of change of mechanical energy states that the total mechanical energy of a system remains constant if no external forces act on it. Mechanical energy is the sum of kinetic energy (energy of motion) and potential energy (stored energy due to position or configuration). The energy of the flywheel-load system changes during movement due to the conversion of mechanical energy between the flywheel and the load. For example, when the flywheel is rotating, it has kinetic energy. As it interacts with the load, some of this kinetic energy may be transferred to the load, causing it to move or perform work. Conversely, the load may transfer energy back to the flywheel, causing its kinetic energy to increase. The total mechanical energy of the system remains constant, but the distribution of energy between the flywheel and the load changes during movement.