Mechanical sound waves are unable to travel through a vacuum such as through space but radio waves are transmitted to earth from satellites how is this possible

Sorry i don’t know what to do

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.