explain the difference between distance and displacement

Answer 1

distance is a scalar. It only has magnitude (like miles). In a car you can measure it with the odometer.
displacement is a vector. It has magnitude AND DIRECTION from start point to finish point. (like miles northeast by east). In a car you need both the odometer and a compass, and do not turn the steering wheel.
If you start at your house and drive half a mile north then half a mile south your distance = 1 mile but your displacement is ZERO.