What is the difference between distance and displacement?

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter

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?

Acoil suspended freely, points in some direction when no current is passed through it . can you tell what will happen when a current is passed though it?