The initial velocity in the y direction is equal to zero why?

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

Distinguish between a transverse wave and a longitudinal wave.

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.