The surface of objects in contact are not completely smooth true or false

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

Two forces produce equal torques on a door about the door hinge. the first force is applied at the midpoint of the door; the second force is applied at the doorknob. both forces are applied perpendicular to the door. which force has a greater magnitude?

Frank just graduated from eighth grade. assuming exactly four years from now he will graduate from high school how many seconds does he have until his high school graduation