Upon arrival at the star Alpha Centauri, which is 4 light years away, an astronaut sends a radio message back to Earth. The message is received 9 years after the astronaut departed Earth. How fast did the astronaut travel

Alightning strike consists of charge moving from a cloud to the ground . in one particular case, the electrons in a lightning strike are confined to travel within a radius of 1.5 m and to move at a speed of 5.0 x 10 m/s. if the density of electrons in the strike is 10'15 electrons/m what current is carried by the lightning ?

Compare the horizontal displacement of the two balls as they travel to the ground. what do you observe?

Two trains leave a station at the same time, train a travels at a constant speed of 16 m/s. train b starts at 8.0 m/s but accelerates constantly at 1.0 m/s squared. after 10.0 seconds, which train has the greater speed?