Q. A helium atom (mass 4.0 u) moving at 599 m/s to the right collides with an oxygen molecule (mass 32 u) moving in the same direction at 400 m/s. After the collision, the oxygen molecule moves at 444 m/s to the right. What is the velocity of the helium atom after the collision?
Q. A circuit contains a 10 Ohm heater and six 240 Ohm lamps, each containing a 60 Watt bulb, all connected in series. The voltage across the circuit is 120 V. What is the current in the circuit when only 4 lamps are turned on? What is the current in the circuit when all the lamps are turned on? What is the current in the circuit when all six lamps and the heater are turned on? If the circuit has a fuse which will melt if the current exceeds 12 A, will the fuse melt?