The process washing rock and dirt from the earth surface

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

Hydrogen and helium are both members of?

Abicycle slows down when the rider applies the brakes. what type of energy transformation is involved in this example? a. kinetic energy into heat energy b. heat energy into potential energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy