1. Calcula el trabajo realizado al elevar 75 cm sobre el piso unas pesas de 90 kg. 5. Resuelve nuevamente el problema del ejemplo 1.9, pero esta vez utilizando la ley de conservación de la energía mecánica.

9. Sobre una mesa se tiene un péndulo formado por un pequeño cuerpo que cuelga de un hilo. El cuerpo queda a 20 cm de la superficie de la mesa. El péndulo se desvía de su posición de equilibrio, elevando el cuerpo 15 cm y luego se suelta. Justamente en el instante que el cuerpo pasa por la posición de equilibrio, se desprende del hilo. ¿A qué distancia horizontal cae sobre la mesa?

13. Si el tiempo empleado por una persona en levantar una maleta de 50 kg a 40 cm sobre el suelo fue 0.50 s, ¿qué potencia media desarrolló?

The ballistic pendulum was invented in 1742 by english mathematician benjamin robins. it consists of an initially stationary pendulum that moves after being struck by a bullet, and it is used to measure the original velocity of the bullet. the known variables are the bullet's mass m, the pendulum's mass m, and the height to which the block and bullet swing, determined by the length of the pendulum l and final angle θ. two principles of physics are necessary to solve for the bullet's original velocity. what are these principles? conservation of momentum and newton's third law conservation of energy and conservation of angular momentum grade summary deductions 0% potential 100% conservation of momentum and newton's second law. newton's second law and conservation of angular momentum. conservation of energy and newton's third law conservation of momentum and conservation of angular momentum. conservation of momentum and conservation of energy conservation of energy and newton's second law.

Alinearly polarized electromagnetic wave has an average intensity of 196 w/m^2. this wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). polarizer a is oriented with its transmission axis at an angle of θ_1=20.8∘ with the incident electric field. polarizer b has its axis at an angle of θ_2=63.0∘ with the incident electric field. what is the average intensity of the wave after it passes through polarizer a? what is the average intensity of the wave after it passes through polarizer b? suppose that the two polarizers a and b are interchanged. what would the average intensity be after passing through both polarizers?

How are series and parallel circuits simililar? both have multiple paths for electrons to travel. both require resistors in their circuits. both require a switch to complete the circuit. both have at least one path for electrons to travel.