A 13,500 kg dumptruck travels on route 322 at a velocity of 4.5m/s. it collided and couples with a 25,000 kg tractor trailor stopped at a red light. what is the momentum of the tractor trailer before the collision

An electromagnet is a device in which moving electric chargers in a coil of wire create a magnet.whats one advantage of using electromagnetic in devices

Could we see a galaxy that is 20 billion light-years away?

The horizontal blue line through the middle of the lens is called the optical axis. as the lamp is moved above or below the axis, keeping the horizontal distance to the center of the lens constant, how does the horizontal distance from the lens to the image change?