What happens when to lightning when it is coming towards the ground?

A1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. the spring has an undeformed length of 5 in. and a constant k =25 lb/ft. knowing that the collar is released from being held at a determine, the speed of the collar and the normal force between the collar and the rod as the collar passes through b.

Ais a machine that makes work easier when a single force is applied. a simple machine b compound machine c endangered machine d complex machine

Due in 40 explain in terms of frame of reference if you’re inside a moving train everything on the outside can seem to be moving