Alfred The Astronaut has a mass of 100 kg and is moving at 10 m/s toward Bertha the Cosmonaut who is at rest and has a mass of 150kg. As he
passes Alfred holds onto Bertha in an INELASTIC collision. What is the
velocity of the astronauts after the collision

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

Where do magnetic lines of force enter earth?

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same