. An electron and its antiparticle, positron are each accelerated to a speed of 0.20 c relative to the lab. They are directed at each other and collide. After the collision two equal photons are produced. (a) What is the total energy just before the collision of the particles? (b) What is the wavelength of the photons after the collision?

How would doubling the made of an object change the objects potential energy

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?