What is the difference about the center of a quasar, when contrasted with a spiral galaxy?

Two balls, each with a mass of 0.5 kg, collide on a pool table. is the law of conservation of momentum satisfied in the collision? explain why or why not

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).

When the acceleration of a mass on a spring is zero, the velocity is at a (fill in the blank) . when the velocity of a mass on a spring is zero, the acceleration is at a (fill in the blank) .