. If you were in a spaceship and launched a cannonball into frictionless space, how much force would have to be exerted on the ball to keep going

What is hidden during a lunar eclipse? isn't the moon hidden?

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

When the magnetic domains in a material can be aligned, but eventually drift out of alignment, the material is