Answer:
Newton’s third law of motion states that every action has an equal and opposite reaction. This indicates that forces always act in pairs. Reaction forces are equal and opposite, but they are not balanced forces because they act on different objects so they don’t cancel each other out.
The velocity is a vectorial quantity, whereas speed is a scalar quantity, meaning it depends on the direction!
As such, the velocity is changing because the direction is changing.
Firstly, do you understand the concept of a wavelength?
Work is (force applied) x (distance through which the force moves).
Since the suitcase doesn't move up or down during the 15 minutes,
no work is done ... zero, zip, nada ... according to the real Physics
definition of 'work'.
